Help with code(newbie stuff)

I

isaac2004

hi im pretty new to the c++ game and i had a question. i have built a
program to bring in data from a file that was required for a class im
in. any way it is basic setting up of an object with 3 classes,
courses, quarters and students. i am wondering if someone could go
over my code and give me some pointers. what i have works fine i juts
want feedback

/* Isaac Levin
W00647376
CS 341
Program 2
April 22nd 2007
*/
////---------Area for Includes////////////////////////////////////
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
using namespace std;

////////Area for Variables///////////////////////////////////////

/* All these variables are for is to set up the formatting of the
output file
All are positions on a line of output
*/


const int Name_Length = 19; //max length of name string
const int Quarter_ID_Length = 4; // max length of an ID for a
Quarter
const int Course_ID_Length = 8; // max length for an ID for a Course
const int Credits_Length = 1; // max length of a string of credits
const int Grades_Length = 2; // max length of a grade string
const int Start_Name = 0; // starting position of the name on the
output line
const int Start_Quarter_ID = 19; // starting position of the Quarter
ID on the output line
const int Start_course_ID = 24; // starting position of the Course
ID on the output line
const int Start_Credits = 34; // starting position of the Credits
on the output line
const int Start_Grade = 39; // starting position of the Grade on
the output line

/////////////////////////////////////////////////////////////////////

string intToString (int x) {
ostringstream output_string;
output_string << x;
return output_string.str();
}
/* Changes a Integer to a string
Pre - int x is brought in
Post - returns the integer converted to a string
*/

int stringToInt (string x) {
istringstream input_string(x);
int i;
input_string >> i;
return i;
}
/* Changes a string to an integer
Pre - string x is brought in
Post - returns the string converted to an integer
*/

//////////Class for the Course Portion

class Course {
public:
Course (string id, int crds, string grd);
/* Constructor Function
Pre - id is a string, crds is an int, and grd is a string as
well
Does not return but creates a Course Object
*/
string toString() const;
/* Formats a string properly for Output
Pre - string is broght in
Post - returns the the string in proper format
*/
string getId() const;
/* Grabs the ID of a Course
Pre - string is brought in
Post - returns the the ID in the form of a string
*/
bool operator< (const Course& right) const;
/*
Pre - Course Object is brought in
Post - returns a boolean if an id is less than the id of the
course object next to it
*/
private:
string course_id;
int credits;
string grade;
};

//--------------Implementation of Class

// constructor
Course::Course (string id, int crds, string grd)
:course_id(id), credits(crds), grade(grd){
}

bool Course::eek:perator< (const Course& right) const {
return course_id < right.course_id; // check if course_id is less
than course.course_id
}

string Course::toString() const {
return " " + course_id + " " + intToString (credits) + " "
+ grade + "\n"; // string is fixed now
}

string Course::getId() const{
return course_id; // return quarter id
}

////////////Class for Quarter Portion

class Quarter {
public:
Quarter (string id);
/* Constructor of a Quarter
Pre - string is brought in
Post - Returns a partial string with a value
*/
void addCourse (string course_id, int credits, string grade);
/* Mutator makes adds a course object with a id, credit amount
and a grade to the quarter
Pre - string called course_id is brought in, as well as an int
for credits and another string for a grade
Does not return just changes the object
*/
string getId() const;
/* Grabs the ID of a Quarter
Pre - string is brought in
Post - returns the the Quarter in the form of a string
*/
string toString() const;
/* Function to clean up the format of a Course string for output
Pre - Course string is brought in
Post - returns a string that has been cleaned up for proper
output
*/
void sort();
/* Crappy algorithm i found online for bubble sort
Pre - Brings in a vector of type quarters
Post - returns vector sorted by course name
*/
bool operator< (const Quarter& right) const;
/* Pre - Quarter Object is brought in
Post - returns a boolean if an id is less than the id of the
quarter object next to it
*/
private:
string quarter_id_Input_format() const;
string quarter_id;
vector<Course> courses;
};

//----------Implementation of Quarter Class


// constructor
Quarter::Quarter (string id) : quarter_id(id){
}

string Quarter::quarter_id_Input_format() const {
string s;

if (quarter_id[0] == 'W' || quarter_id[0] == 'w')
s = "1";
else if (quarter_id[0] == 'S' || quarter_id[0] == 's')
s = "2";
else
s = "3";
// conditional to give value of quarters via time of taken
return quarter_id.substr (1, 3) + s; // returns partial string of
quarter_id concatenated with the value of the id
}

bool Quarter::eek:perator< (const Quarter& right) const {
return quarter_id_Input_format() < right.quarter_id_Input_format();
}

void Quarter::addCourse (string course_id, int credits, string grade)
{
courses.push_back (Course (course_id, credits, grade)); // adds the
courses vector to each quarter object
} // adds the records to the course object

string Quarter::getId() const {
return quarter_id;
}
// function just returns the id of the quarter

string Quarter::toString() const {
string s = " " + quarter_id + "\n"; // formats the way the
quarter will look
for (int x = 0; x < (int)(courses.size()); x++) //loop through
courses vector intil done
s = s + courses[x].toString(); // loops through formatting s
return s;
}
// naive bubble sort from the internet
// brings in vector and sorts via course name
void Quarter::sort() {
for (int x = 0; x < (int)(courses.size() - 1); x++){
for (int y = x + 1; y < (int)(courses.size()); y++) {
if (courses[y] < courses[x]) { // if one string is less than
the other
Course temp = courses[x]; // next few lines move the too
or swap
courses[x] = courses[y];
courses[y] = temp;
}
}
}
}

////////////Class for Student Portion

class Student {
public:
Student (string name);
/* Constructor of a Student
Pre - string is brought in
does not return just creates object
*/
string getName() const;
/* Constructor of a Quarter
Pre - string is brought in
Post - Returns a string for the name
*/
void addCourse (string quarter_id, string course_id, int credits,
string grade);
/* Mutator makes adds a course object with a id, credit amount and
a grade to the quarter
Pre - string called course_id is brought in, as well as an int
for credits and another string for a grade
Does not return just changes the object
*/
string toString() const;
/* Function to clean up the format of a student string for output
Pre - student string is brought in
Post - returns a string that has been cleaned up for proper
output
*/
void sort();
/* Crappy algorithm i found online for bubble sort
Pre - Brings in a vector of type quarters
Post - returns vector sorted by quarter
*/
bool operator< (const Student& right) const;
/* Pre - Student Object is brought in
Post - returns a boolean if a name is less than the name of the
student object next to it
*/
private:
int getQuarterIndex (string quarter_id);
string name;
vector<Quarter> quarters;
};

//---------Implementation of Student Class

// constructor
Student::Student (string name) : name(name) {
}

bool Student::eek:perator< (const Student& right) const {
return name < right.name; // returns a boolean representing if name
is less than the object next to it
}

void Student::addCourse (string quarter_id, string course_id, int
credits, string grade) {
int x = getQuarterIndex (quarter_id);
quarters[x].addCourse (course_id, credits, grade); // adds quarters
on the end of that
}

string Student::getName() const {
return name;// returns name of the object
}

int Student::getQuarterIndex (string quarter_id) {
for (int x = 0; x < (int)(quarters.size()); x++) {
if (quarter_id == quarters[x].getId())// if quarter_id variable
is equal to the id of array part
return x; // then return index of
array
}
quarters.push_back (Quarter (quarter_id)); // adds the quarter to
the student record
return (int)(quarters.size() - 1);
}

string Student::toString() const {
string s = name + "\n";
for (int x = 0; x < (int)(quarters.size()); x++)
s = s + quarters[x].toString(); // makes a call to itself with a
concatentation of the string
return s;
}
// sort again this time it sorts by strength of a quarter
void Student::sort() {
for (int x = 0; x < (int)(quarters.size()); x++){
for (int y = x + 1; y < (int)(quarters.size()); y++) {
if (quarters[y] < quarters[x]) { // if one value is lower
than the other
Quarter temp = quarters[x]; // next lines are for
swapping
quarters[x] = quarters[y];
quarters[y] = temp;
}
}
}
}

//////////helper functions for main

int getStudentIndex (string name, vector<Student>& students) {
/* brings in a string from input and compares to the vector
Pre - string brought in to compare
Post - int created that represented index of vector
*/
for (int x = 0; x < (int)(students.size()); x++) {
if (name == students[x].getName())
return x;
}
students.push_back (Student (name)); // continue process
return (int)(students.size() - 1);
}

bool readLine (ifstream& input, vector<Student>& students) {
string name, quarter_id, course_id, grade;
int credits;
string column;
/* reads in a stream from an input file
Pre - Input file is needed
Post - Puts and orders all data into the structure that is built
and returns true
*/
if (!getline (input, column)) return false; // if end of stream
name = column.substr (Start_Name, Name_Length); // grabs range of
values and puts them in name
quarter_id = column.substr (Start_Quarter_ID,
Quarter_ID_Length); // grabs range of values and puts them in
quarter_id
course_id = column.substr (Start_course_ID, Course_ID_Length);//
grabs range of values and puts them in course_id
credits = stringToInt (column.substr(Start_Credits,
Credits_Length));// grabs range of values and puts them in credits
if (column.length() == Start_Grade + 1)// if length of column
position is equal to max length + 1 then
column += " "; // extend column
grade = column.substr (Start_Grade, Grades_Length);// grabs range
of values and puts them in grade
int i = getStudentIndex (name, students); // calls function and
puts returned int into i
students.addCourse (quarter_id, course_id, credits, grade);//
finally adds courses into student object

return true;
}

string toString (const vector<Student>& students) {
/* turns the vector into a string
Pre - brings in the vector
Post - converts the vector to a string
*/
string s = "";
for (int i = 0; i < (int)(students.size()); i++)
s = s + students.toString();
return s;
}
//same sort from earlier, just changed to use Students
void sort (vector<Student>& students) {
/* sorts a vector
Pre - brings in a vector
Post - sorts the vector and does not return anything
*/
for (int i = 0; i < (int)(students.size()); i++){
for (int j = i + 1; j < (int)(students.size()); j++) {
if (students[j] < students) {
Student temp = students;
students = students[j];
students[j] = temp;
}
}
}
}

/////////////////////////////////////////////////////////////////////

int main() {
ifstream input;
input.open ("grades.dat");
vector<Student> students;

while (readLine (input, students));
// loops through and reads in the file and adds it to a vector

sort (students);// sorts the vector
cout << toString(students); // outputs vector

return 0;
}

the input is a data file
Smith, Sue S'04 CSCI 204 4 B+
Anderson, Adam S'03 EDAD 450 2 D-
Madison, Mitch W'04 PHYS 123 5 B
Anderson, Adam F'03 ENG 310 3 C-
Anderson, Adam W'02 AMST 204 3 A-
Anderson, Adam F'03 ESCI 154 4 B
Anderson, Adam F'03 ART 101 3 B+
Madison, Mitch F'03 GEOL 350 5 F

the output should be all the values are sorted, first by name, then
quarters and class.

thanks for the help
 
G

Gianni Mariani

isaac2004 said:
hi im pretty new to the c++ game and i had a question. i have built a
program to bring in data from a file that was required for a class im
in. any way it is basic setting up of an object with 3 classes,
courses, quarters and students. i am wondering if someone could go
over my code and give me some pointers. what i have works fine i juts
want feedback

/* Isaac Levin
W00647376
CS 341
Program 2
April 22nd 2007
*/
////---------Area for Includes////////////////////////////////////
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
Click to expand...

Importing the entire std namespace is valid and I do it for little
example programs, however I never do it for production code.
////////Area for Variables///////////////////////////////////////

/* All these variables are for is to set up the formatting of the
output file
All are positions on a line of output
*/


const int Name_Length = 19; //max length of name string
const int Quarter_ID_Length = 4; // max length of an ID for a
Quarter
const int Course_ID_Length = 8; // max length for an ID for a Course
const int Credits_Length = 1; // max length of a string of credits
const int Grades_Length = 2; // max length of a grade string
const int Start_Name = 0; // starting position of the name on the
output line
const int Start_Quarter_ID = 19; // starting position of the Quarter
ID on the output line
const int Start_course_ID = 24; // starting position of the Course
ID on the output line
const int Start_Credits = 34; // starting position of the Credits
on the output line
const int Start_Grade = 39; // starting position of the Grade on
the output line

/////////////////////////////////////////////////////////////////////

string intToString (int x) {
ostringstream output_string;
output_string << x;
return output_string.str();
}
/* Changes a Integer to a string
Pre - int x is brought in
Post - returns the integer converted to a string
*/
Click to expand...

Put comments before the function.
int stringToInt (string x) {
istringstream input_string(x);
int i;
input_string >> i;
return i;
}
Click to expand...

How do you know if the conversion failed ? Do you want to throw an
exception on failure ?
/* Changes a string to an integer
Pre - string x is brought in
Post - returns the string converted to an integer
*/
Click to expand...

Again - put this at the top of the function.
//////////Class for the Course Portion

class Course {
public:
Course (string id, int crds, string grd);
/* Constructor Function
Pre - id is a string, crds is an int, and grd is a string as
well
Does not return but creates a Course Object
*/
string toString() const;
/* Formats a string properly for Output
Pre - string is broght in
Post - returns the the string in proper format
*/
string getId() const;
/* Grabs the ID of a Course
Pre - string is brought in
Post - returns the the ID in the form of a string
*/
bool operator< (const Course& right) const;
/*
Pre - Course Object is brought in
Post - returns a boolean if an id is less than the id of the
course object next to it
*/
private:
string course_id;
int credits;
string grade;
};

//--------------Implementation of Class

// constructor
Course::Course (string id, int crds, string grd)
:course_id(id), credits(crds), grade(grd){
}

bool Course::eek:perator< (const Course& right) const {
return course_id < right.course_id; // check if course_id is less
than course.course_id
}

string Course::toString() const {
return " " + course_id + " " + intToString (credits) + " "
+ grade + "\n"; // string is fixed now
}

string Course::getId() const{
return course_id; // return quarter id
}

////////////Class for Quarter Portion

class Quarter {
public:
Quarter (string id);
/* Constructor of a Quarter
Pre - string is brought in
Post - Returns a partial string with a value
*/
void addCourse (string course_id, int credits, string grade);
/* Mutator makes adds a course object with a id, credit amount
and a grade to the quarter
Pre - string called course_id is brought in, as well as an int
for credits and another string for a grade
Does not return just changes the object
*/
string getId() const;
/* Grabs the ID of a Quarter
Pre - string is brought in
Post - returns the the Quarter in the form of a string
*/
string toString() const;
/* Function to clean up the format of a Course string for output
Pre - Course string is brought in
Post - returns a string that has been cleaned up for proper
output
*/
void sort();
/* Crappy algorithm i found online for bubble sort
Pre - Brings in a vector of type quarters
Post - returns vector sorted by course name
*/
bool operator< (const Quarter& right) const;
/* Pre - Quarter Object is brought in
Post - returns a boolean if an id is less than the id of the
quarter object next to it
*/
private:
string quarter_id_Input_format() const;
string quarter_id;
vector<Course> courses;
};

//----------Implementation of Quarter Class


// constructor
Quarter::Quarter (string id) : quarter_id(id){
}

string Quarter::quarter_id_Input_format() const {
string s;

if (quarter_id[0] == 'W' || quarter_id[0] == 'w')
s = "1";
else if (quarter_id[0] == 'S' || quarter_id[0] == 's')
s = "2";
else
s = "3";
// conditional to give value of quarters via time of taken
return quarter_id.substr (1, 3) + s; // returns partial string of
quarter_id concatenated with the value of the id
}

bool Quarter::eek:perator< (const Quarter& right) const {
return quarter_id_Input_format() < right.quarter_id_Input_format();
}

void Quarter::addCourse (string course_id, int credits, string grade)
{
courses.push_back (Course (course_id, credits, grade)); // adds the
courses vector to each quarter object
} // adds the records to the course object

string Quarter::getId() const {
return quarter_id;
}
// function just returns the id of the quarter

string Quarter::toString() const {
string s = " " + quarter_id + "\n"; // formats the way the
quarter will look
for (int x = 0; x < (int)(courses.size()); x++) //loop through
courses vector intil done
s = s + courses[x].toString(); // loops through formatting s
return s;
}
// naive bubble sort from the internet
// brings in vector and sorts via course name
void Quarter::sort() {
for (int x = 0; x < (int)(courses.size() - 1); x++){
for (int y = x + 1; y < (int)(courses.size()); y++) {
if (courses[y] < courses[x]) { // if one string is less than
the other
Course temp = courses[x]; // next few lines move the too
or swap
courses[x] = courses[y];
courses[y] = temp;
}
}
}
}

////////////Class for Student Portion

class Student {
public:
Student (string name);
/* Constructor of a Student
Pre - string is brought in
does not return just creates object
*/
string getName() const;
/* Constructor of a Quarter
Pre - string is brought in
Post - Returns a string for the name
*/
void addCourse (string quarter_id, string course_id, int credits,
string grade);
/* Mutator makes adds a course object with a id, credit amount and
a grade to the quarter
Pre - string called course_id is brought in, as well as an int
for credits and another string for a grade
Does not return just changes the object
*/
string toString() const;
/* Function to clean up the format of a student string for output
Pre - student string is brought in
Post - returns a string that has been cleaned up for proper
output
*/
void sort();
/* Crappy algorithm i found online for bubble sort
Pre - Brings in a vector of type quarters
Post - returns vector sorted by quarter
*/
bool operator< (const Student& right) const;
/* Pre - Student Object is brought in
Post - returns a boolean if a name is less than the name of the
student object next to it
*/
private:
int getQuarterIndex (string quarter_id);
string name;
vector<Quarter> quarters;
};

//---------Implementation of Student Class

// constructor
Student::Student (string name) : name(name) {
Click to expand...

While the initializer is valid i.e. name(name), I have seen compilers
get this one wrong (older ones). For mere humans, use different names
for parameters than you do for members.
}

bool Student::eek:perator< (const Student& right) const {
return name < right.name; // returns a boolean representing if name
is less than the object next to it
}

void Student::addCourse (string quarter_id, string course_id, int
credits, string grade) {
int x = getQuarterIndex (quarter_id);
quarters[x].addCourse (course_id, credits, grade); // adds quarters
on the end of that
}

string Student::getName() const {
return name;// returns name of the object
}

int Student::getQuarterIndex (string quarter_id) {
for (int x = 0; x < (int)(quarters.size()); x++) {
if (quarter_id == quarters[x].getId())// if quarter_id variable
is equal to the id of array part
return x; // then return index of
array
}
quarters.push_back (Quarter (quarter_id)); // adds the quarter to
the student record
return (int)(quarters.size() - 1);
}

string Student::toString() const {
string s = name + "\n";
for (int x = 0; x < (int)(quarters.size()); x++)
s = s + quarters[x].toString(); // makes a call to itself with a
concatentation of the string
return s;
}
// sort again this time it sorts by strength of a quarter
void Student::sort() {
for (int x = 0; x < (int)(quarters.size()); x++){
for (int y = x + 1; y < (int)(quarters.size()); y++) {
if (quarters[y] < quarters[x]) { // if one value is lower
than the other
Quarter temp = quarters[x]; // next lines are for
swapping
quarters[x] = quarters[y];
quarters[y] = temp;
}
}
}
}

//////////helper functions for main

int getStudentIndex (string name, vector<Student>& students) {
/* brings in a string from input and compares to the vector
Pre - string brought in to compare
Post - int created that represented index of vector
*/
for (int x = 0; x < (int)(students.size()); x++) {
if (name == students[x].getName())
return x;
}
students.push_back (Student (name)); // continue process
return (int)(students.size() - 1);
Click to expand...

HORROR - no C++ casts. oooh bad bad. Make the function return size_t.
Avoid using casts unless your writing a very small class for managing
some system dependant thing.
}

bool readLine (ifstream& input, vector<Student>& students) {
string name, quarter_id, course_id, grade;
int credits;
string column;
/* reads in a stream from an input file
Pre - Input file is needed
Post - Puts and orders all data into the structure that is built
and returns true
*/
if (!getline (input, column)) return false; // if end of stream
name = column.substr (Start_Name, Name_Length); // grabs range of
values and puts them in name
quarter_id = column.substr (Start_Quarter_ID,
Quarter_ID_Length); // grabs range of values and puts them in
quarter_id
course_id = column.substr (Start_course_ID, Course_ID_Length);//
grabs range of values and puts them in course_id
credits = stringToInt (column.substr(Start_Credits,
Credits_Length));// grabs range of values and puts them in credits
if (column.length() == Start_Grade + 1)// if length of column
position is equal to max length + 1 then
column += " "; // extend column
grade = column.substr (Start_Grade, Grades_Length);// grabs range
of values and puts them in grade
int i = getStudentIndex (name, students); // calls function and
puts returned int into i
students.addCourse (quarter_id, course_id, credits, grade);//
finally adds courses into student object

return true;
}

string toString (const vector<Student>& students) {
/* turns the vector into a string
Pre - brings in the vector
Post - converts the vector to a string
*/
string s = "";
for (int i = 0; i < (int)(students.size()); i++)
s = s + students.toString();
return s;
}
//same sort from earlier, just changed to use Students
void sort (vector<Student>& students) {
/* sorts a vector
Pre - brings in a vector
Post - sorts the vector and does not return anything
*/
for (int i = 0; i < (int)(students.size()); i++){
for (int j = i + 1; j < (int)(students.size()); j++) {
if (students[j] < students) {
Student temp = students;
students = students[j];
students[j] = temp;
}
}
}
Click to expand...


Use std::sort().
}

/////////////////////////////////////////////////////////////////////

int main() {
ifstream input;
input.open ("grades.dat");
vector<Student> students;

while (readLine (input, students));
// loops through and reads in the file and adds it to a vector

sort (students);// sorts the vector
cout << toString(students); // outputs vector

return 0;
}

the input is a data file
Smith, Sue S'04 CSCI 204 4 B+
Anderson, Adam S'03 EDAD 450 2 D-
Madison, Mitch W'04 PHYS 123 5 B
Anderson, Adam F'03 ENG 310 3 C-
Anderson, Adam W'02 AMST 204 3 A-
Anderson, Adam F'03 ESCI 154 4 B
Anderson, Adam F'03 ART 101 3 B+
Madison, Mitch F'03 GEOL 350 5 F

the output should be all the values are sorted, first by name, then
quarters and class.

thanks for the help
Click to expand...

The biggest issue I see is that the code does not handle bad input data
and quietly says (return 0) success.

If you want to comment your code, then take some time to learn the
doxygen commenting style, it's very easy and you can get a good analysis
of your code.

I only skimmed through this, however it does seem like you have done a
pretty good job overall.
 

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