C语言 strncat()函数

char *strncat(char *str1, const char *str2, size_t n)

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

int main () {
   char str1[50], str2[50];

   //destination string
   strcpy(str1, "This is my initial string");

   //source string
   strcpy(str2, ", add this");

   //displaying destination string
   printf("String after concatenation: %s\n", strncat(str1, str2, 5));

   // this should be same as return value of strncat()
   printf("Destination String str1: %s", str1);

   return 0;
}

String after concatenation: This is my initial string, add
Destination String str1: This is my initial string, add