strcat

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void) {
    char* c = (char*)malloc(16 * sizeof(char));
    char* c1 = "hoge";
    char* c2 = "fuga";

    strcat(c, c1);
    strcat(c, c2);

    printf("%s", c);

    return 0;
}