#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
 
 
char *my_strcat(char *dest, char *src)
{
    assert(dest);
    assert(src);
    char *ret = src;
    while (*src)
    {
        src++;
    }
    while (*src++ = *dest++)
    {
        ;
    }
    return ret;
}
 
int main()
{
    char arr1[20] = "hello ";
    char arr2[] = "world!";
    char *ret = my_strcat(arr2, arr1);
    printf("%s", ret);
    system("pause");
    return 0;
}