strncat c
#include <stdio.h>
#include <string.h>
int main () {
   char src[50], dest[50];
   strcpy(src,  "This is source");
   strcpy(dest, "This is destination");
   strncat(dest, src, 15);
   printf("Final destination string : |%s|", dest);
   
   return(0);
}
output:
Final destination string : |This is destinationThis is source|
