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

int main(void) {
	char *str1 = "hello ";
	char *str2 = "world!";
	unsigned int i1 = strlen( str1 );
	unsigned int i2 = strlen( str2 );
	
	char a[i1+i2+1];
	sprintf( a, "%s%s", str1, str2 );
	printf( "%s", a );
	return 0;
}