Changing gets() to txt file input [closed] - c

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I need to covert this code from a user input using gets() to scanning in an input txt file.
It would also be helpful to find a way to count the number of letters in every word. Starting with 1 letter words and on.
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
int main(void) {
int acount, bcount, ccount, dcount, ecount, fcount, gcount, hcount, icount, jcount, kcount, lcount, mcount, ncount, ocount, pcount, qcount, rcount, scount, tcount, ucount, vcount, wcount, xcount, ycount, zcount = 0;
char *str;
printf("Enter any string : ");
gets(str);
while (*str != '\0')
{
if(isalpha(*str))
{
toupper(*str);
switch(*str)
{
case 'A':
++acount;
break;
case 'B':
++bcount;
break;
case 'C':
++ccount;
break;
case 'D':
++dcount;
break;
case 'E':
++ecount;
break;
case 'F':
++fcount;
break;
case 'G':
++gcount;
break;
case 'H':
++hcount;
break;
case 'I':
++icount;
break;
case 'J':
++jcount;
break;
case 'K':
++kcount;
break;
case 'L':
++lcount;
break;
case 'M':
++mcount;
break;
case 'N':
++ncount;
break;
case 'O':
++ocount;
break;
case 'P':
++pcount;
break;
case 'Q':
++qcount;
break;
case 'R':
++rcount;
break;
case 'S':
++scount;
break;
case 'T':
++tcount;
break;
case 'U':
++ucount;
break;
case 'V':
++vcount;
break;
case 'W':
++wcount;
break;
case 'X':
++xcount;
break;
case 'Y':
++ycount;
break;
case 'Z':
++zcount;
break;
}//Close case
}//Close if
}//Close while
printf("Number of A's: %d", acount);
}

Answer 1

Many errors in your code
You don't initialize all the (x)count variables to 0, read about the coma operator.
You used gets() which is a mean and deprecated function.
You passed an uninitialized pointer to gets() which is undefined behavior.
toupper(*str) does not modify *str.
Try this one
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
int main(void)
{
/* You need an array of int's with size equal to the number of letters
* int the alphabet
*/
int count['Z' - 'A' + 1];
/* You need some space to store the text, `str' will become a poitner
* when you pass it to `fgets()' pointing to an array of 1000 `chars'
*/
char str[1000];
/* Initialize all the counters to 0 */
for (int i = 0 ; i < sizeof(count) / sizeof(*count) ; ++i)
count[i] = 0;
printf("Enter any string : ");
/* Read the string, use `fgets()` and prevent a buffer overflow */
if (fgets(str, sizeof(str), stdin) == NULL)
return -1;
/* Now count the letters */
for (int i = 0 ; ((str[i] != '\0') && (str[i] != '\n')) ; ++i)
{
/* If it's not a letter, go to the next one */
if (isalpha((int) str[i]) == 0)
continue;
/* It's a letter, count it at the correct position */
count[toupper((int) str[i]) - 'A'] += 1;
}
/* Print the count of each letter, skipping those that did not appear */
for (int i = 0 ; i < sizeof(count) / sizeof(*count) ; ++i)
{
if (count[i] == 0)
continue;
fprintf(stderr, "Number of %c's : %d\n", i + 'A', count[i]);
}
return 0;
}

Answer 2

All remarks in iharob response are correct. Read my comment on his response for extra problems. Here is a simple solution:
#include <stdio.h>
int main(void) {
int counts[256] = { 0 };
int c;
printf("Enter any string: ");
while ((c = getchar()) != EOF && c != '\n') {
counts[c & 255]++;
}
printf("Number of A's: %d", counts['a'] + counts['A']);
return 0;
}
EDIT: here is a solution to handle a file instead of a line of input:
#include <stdio.h>
int main(int argc, char **argv) {
long long int counts[256] = { 0 };
int c;
FILE *f;
if (argc < 2) {
fprintf(stderr, "usage: %s FILE\n", argv[0]);
exit(2);
}
if ((f = fopen(argv[1], "r")) == NULL) {
fprintf(stderr, "%s: cannot open %s\n", argv[0], argv[1]);
exit(1);
}
while ((c = getc(f)) != EOF) {
counts[c & 255]++;
}
fclose(f);
printf("Number of A's: %lld", counts['a'] + counts['A']);
return 0;
}