strchr

I know that strchr, searches for the first occurences of a char in a string... I just wanted know if I can use this code to count characters in a string as example.

String: An apple a day keeps the doctor away

Char to search: a

Result: Found a 6 times in String.

1. I have figured out something like this.

Code:

---

#include <string.h>
#include <stdio.h>

int main(void)
{
  char string[15];
  char *ptr, c = 'i';
  int i;

  strcpy(string, "This is a string");
  ptr = strchr(string, c);
  if (ptr)
      while(ptr)
          {
            ptr = strchr(string, NULL);
            i++;
            }
      printf("Char %c, found %d times in string", c, i);
  else
      printf("Char was not found in string");
}

---

But this code didn't work... so I just need a bugfix in this code could you help me out a little bit ???

2. How do I get this code to find also the Uppercase and the Lowercase 'A' in this code ?

Thanks in advance
Client

Do you have to use strchr? its easy enough to do without it

Code:

---

#include <stdio.h>
#include <ctype.h>

int main( void )
{
       
        char string[] = "An apple a day keeps the doctor away";
        char *p = string;
        char ch;
        int count = 0;
       
        printf( "\nEnter character to search for: ");
        ch = getchar();
        ch = tolower( ch ); //ensure ch is lowercase

        // all processing done here
        while( *p )
        {
                if( tolower( *p ) == ch  ) //test ch against a lowercase *p
                        ++count;          // if the same increment count

                ++p;
        }

        //display results
        printf( "\n%c occured %d times in the string \"%s\"\n", ch, count, string );

        return 0;
}

---

Or the strchr() method:

Code:

---

#include <string.h>
#include <stdio.h>

int main(void)
{
        char        string[30];
        char        *ptr, c = 'i';
        int        i = 0;

        strcpy(string, "This is a string");
        ptr = strchr(string, c);
        while ((ptr = strchr(ptr, c)) != NULL)
                {i++;ptr++;}

        printf("Char %c, found %d times in string", c, i);
       
        return (0);
}

---

Three main things wrong with the original code.
- string was 15 bytes long, but the text strcpy()'d into was 16 bytes. Instant buffer overflow... oops.
- i was not initialised before use. You must set it to 0 first!
- incorrect args passed to strchr().

Have fun.........