D
Developwebsites
no i am doing top secret work for the CIA.
no i am doing top secret work for the CIA.
D
Developwebsites
/*
I am trying to input names of 5 cities in a for loop, store them in an array,
(not a vector as we havent got there yet), and then print them out.
is this the correct way of doing it:
*/
#include<iostream>
#include<iomanip>
#include<string>
using namespace std;
class Cities {
private:
string *city;
public:
Cities();
void input();
void output();
};
Cities:: Cities()
{
}
void Cities::input()
{
int total=0;
do{
cout<<"\n";
cout<<"Please enter name of city: ";
cin>>city[total];
total++;
}while(total<5);
cout<<"\n\n";
}
void Cities:
utput()
{
cout<<"\n";
cout<<"name of city"
<<"\n";
for(int t=0;t<5;t++)
{
cout<<setw(5)<<city[t]<<"\n";
}
}//close output
int main()
{
Cities info;
info.input();
info.output();
return 0;
}
I am trying to input names of 5 cities in a for loop, store them in an array,
(not a vector as we havent got there yet), and then print them out.
is this the correct way of doing it:
*/
#include<iostream>
#include<iomanip>
#include<string>
using namespace std;
class Cities {
private:
string *city;
public:
Cities();
void input();
void output();
};
Cities:: Cities()
{
}
void Cities::input()
{
int total=0;
do{
cout<<"\n";
cout<<"Please enter name of city: ";
cin>>city[total];
total++;
}while(total<5);
cout<<"\n\n";
}
void Cities:
utput(){
cout<<"\n";
cout<<"name of city"
<<"\n";
for(int t=0;t<5;t++)
{
cout<<setw(5)<<city[t]<<"\n";
}
}//close output
int main()
{
Cities info;
info.input();
info.output();
return 0;
}
J
Jonathan Mcdougall
/*
Do not multipost. See my answer in alt.comp.lang.learn.c-c++ (that sure is
a long name).
Jonathan
Do not multipost. See my answer in alt.comp.lang.learn.c-c++ (that sure is
a long name).
Jonathan
K
Karl Heinz Buchegger
Developwebsites said:
AS I said:
class City
{
public:
private:
string name;
};
class Cities
{
public:
private:
vector< City > AllCities;
};
There is one class for a single city.
And then there is another class which holds
all those cities.
You say:
Fine. But:
a city name is a property of a single city. Thus you don't want to store
names, you want to store cities. In the near future you might want to
expand your example to: a city has a name *and* an inhabitants number.
Then you are prepared: just add the number of inhabitants to a single
city:
class City
{
public:
private:
string name;
long inhabitants;
};
No need to fiddle with the vector (array) in Cities. Ciities still holds
multiple cities, but a city now contains more information.
K
Karl Heinz Buchegger
Developwebsites said:
That's not an array. It is a pointer to a string. But
at the moment this pointer doesn't even point to 1 string,
it points to nowehere.
If you want an array, you have to create one:
string city[5]; // array to store 5 cities
better would be to use a vector
vector<string> city;
becuase you don't have to keep track about how many city names are stored
by yourself any longer. Also: vector does the dynamic memory management for you.
D
Default User
Developwebsites said:
Overdue, but:
*plonk*
Brian Rodenborn
D
Developwebsites
is the only answer you will get from people like him.
*plonk* right back at you shemp lover.
D
Developwebsites
If you want an array, you have to create one:
what if the user enters more than 5 cities?
number of cities is unknown, and is set at 0, so string *city seemed to solve
the problem, compiles fine, but yes it does crash.
as I've said we did not cover vector and until we do i am not going to use it.
what if the user enters more than 5 cities?
number of cities is unknown, and is set at 0, so string *city seemed to solve
the problem, compiles fine, but yes it does crash.
as I've said we did not cover vector and until we do i am not going to use it.
K
Kevin Goodsell
Developwebsites said:
What if? What if you expand the array to 5 billion and they enter 5
billion and one? This is a limitation of arrays. If you use arrays, you
have to deal with it.
string *city is far worse than string city[5] in that there is NO SPACE
for storing the cities. At least with the array you had room for 5 of
them - with the pointer you don't have room for any. OF COURSE it
crashes when you try to store data through a wild pointer. What did you
expect?
Pointers aren't magical things that point to as much space as you want
or need. They point to exactly what you tell them too, no more, no less.
If you don't tell them to point to anything, they don't. If you try to
access the "thing" that an uninitialized pointer points to, the
program's behavior is undefined and it will probably crash (on most
modern desktop systems).
If you are going to use a pointer to string, you first have to make it
point to the strings you want to use. You could do this:
string *cities;
string some_cities[20];
cities = some_cities;
But obviously you'd be better off just using
string cities[20];
The other alternative is to determine the number of cities at run time:
int num_cities = GetNumberOfCities();
string *cities = new string[num_cities];
But, you'd be better off using a vector, which manages the dynamic array
for you.
You can do it however you want. We're just telling you what would be best.
-Kevin
K
Kevin Goodsell
Developwebsites said:
I've seen a lot of people get good answers from him. He got tired of
your attitude. He's not alone.
-Kevin
W
WW
Developwebsites said:
You have already got all the help here you have paid for.
http://funwavs.com/wavfile.php?quote=666&sound=276
http://funwavs.com/wavfile.php?quote=670&sound=276
D
Default User
Kevin said:
While Shemp was no Curl(e)y, there were some pretty good Shemp episodes.
Eh, I try. I'm most helpful with the C and C++ crossover area, as I'm a
more experienced C programmer than C++. I mostly read to sharpen my
knowledge of weak points, like templates and some of the more obscure
features of standard containers.
It's been my experience that people who behave like jackasses when the
first start posting rarely get better, but sometimes they "see the
light". I always give them a chance by pointing out their behavior. If
it continues, then why waste my time with that person?
The best would be for a mass plonking of the offender, but that's a
personal choice of group participants.
Brian Rodenborn