Here is my version with some timing code (e.g., `clock()'):
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#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#if ! defined (FILE_MODE)
# define FILE_MODE "rb"
#endif
typedef char sassert[
'Z' - 'A' == 25 &&
'z' - 'a' == 25 ? 1 : -1
];
#define BUFFER 65536U
#define GET_COUNT(mp_self, mp_index) ( \
(mp_self)[(mp_index) + 'a'] + \
(mp_self)[(mp_index) + 'A'] \
)
int main(int argc, char** argv) {
if (argc > 1) {
size_t i;
unsigned long total = 0;
unsigned long counts[UCHAR_MAX + 1] = { 0 };
clock_t const start = clock();
FILE* file = fopen(argv[1], FILE_MODE);
if (file) {
size_t size;
int status = EXIT_SUCCESS;
static unsigned char buf[BUFFER];
while ((size = fread(buf, 1, BUFFER, file))) {
size_t tmpsize = size;
while (tmpsize) {
++counts[buf[--tmpsize]];
}
if (size < BUFFER) break;
}
if (ferror(file)) status = EXIT_FAILURE;
if (fclose(file)) status = EXIT_FAILURE;
if (status == EXIT_SUCCESS) {
clock_t stop;
for (i = 0; i < 26; ++i) {
total += GET_COUNT(counts, i);
}
for (i = 0; i < 26; ++i) {
printf("%c %%%.3f\n", (char)(i + 'a'),
(total) ? ((double)GET_COUNT(counts, i) / total)
* 100.0 : 0.0);
}
stop = clock();
printf("\nelapsed time: %lums\n",
(unsigned long)((((double)stop - (double)start)
/ CLOCKS_PER_SEC) * 1000.0));
return EXIT_SUCCESS;
}
}
}
fprintf(stderr, "file error...");
assert(0);
return EXIT_FAILURE;
}
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