自訂一個strcat (c++)

#include <iostream>
using namespace std;

char *strcat2(char *dest, const char*src);
int main(void){

        char* dest = (char *)malloc(256);
        *dest='\0';
        cout<<strcat2(dest,"concat string")<<endl;

        return 0;
}

char *strcat2(char *dest, const char*src){
        char *ret;
        ret = dest;
        while(*dest++);
        dest--;
        while(*dest++= *src++);

        return ret;
}