模拟实现strncat

功能：将字符ct中最多前n个字符连接到字符串s的尾部，并以'\0'结束：该函数返回s

#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
char *my_strncat(char *dst, const char *src, size_t count)
{
assert(NULL!= dst&&NULL != src);
char *ret = dst;
while (*dst)
{
dst++;
}
while (count--&&*src)
{
*dst = *src;
dst++;
src++;
}
*dst = '\0';
return ret;
}
int main()
{
char s[30] = "hello";
char ct[10] = "welcome";
printf("%s", my_strncat(s, ct, 2));
system("pause");
return 0;
}