strncat

#include<stdio.h>
 
#include<string.h>
 
 
int main(void)
 
{
 
        int n;
    char dest[20] = "Hello";
 
    char src[10] = "World";
 
    strncat(dest, src, 5);//n=5为src前n个字符
 
    printf("%s\n", dest);
 
    return  0;
 
}
【运行结果】：HelloWorld