Write a function that finds the last instance of a character in a string?

Question

For example: It returns ‘b’ when the input is “abaccdeff”.

Answer 1

Format

#include <string.h>
char *strrchr(const char *string, int c);

Language Level
ANSI

Threadsafe
Yes

Locale Sensitive
The behavior of this function might be affected by the LC_CTYPE category of the current locale. For more information

Description
The strrchr() function finds the last occurrence of c (converted to a character) in string. The ending null character is considered part of the string.

Return Value
The strrchr() function returns a pointer to the last occurrence of c in string. If the given character is not found, a NULL pointer is returned.

Example
This example compares the use of strchr() and strrchr(). It searches the string for the first and last occurrence of p in the string.

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

#define SIZE 40

int main(void)
{
  char buf[SIZE] = "computer program";
  char * ptr;
  int    ch = 'p';

  /* This illustrates strchr */
  ptr = strchr( buf, ch );
  printf( "The first occurrence of %c in '%s' is '%s'\n", ch, buf, ptr );

  /* This illustrates strrchr */
  ptr = strrchr( buf, ch );
  printf( "The last occurrence of %c in '%s' is '%s'\n", ch, buf, ptr );
}

/*****************  Output should be similar to:  *****************

The first occurrence of p in 'computer program' is 'puter program'
The last occurrence of p in 'computer program' is 'program'
*/