在数组的前n个字节中搜索字符

[c]代码库

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

int main(void) 
{ 
   char str[17]; 
   char *ptr; 

   strcpy(str, "This is a string"); 
   ptr = memchr(str, 'r', strlen(str)); 
   if (ptr) 
      printf("The character 'r' is at position: %d\n", ptr - str); 
   else 
      printf("The character was not found\n"); 
   return 0; 
}