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

int main() {
	const char* s1="Hello, ";
	const char* s2="World!";
	
	size_t len = strlen(s1) + strlen(s2);
	size_t size = sizeof(char) * (len + 1);
	
	char * buf = malloc(size);
	
	strcpy(buf, s1);
	strcat(buf, s2);
	
	printf("%s\r\n", buf);
	
	free(buf);
	
	return 0;
}