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

#define NO_ERROR 0
#define NULL_PTR_ERROR -1

typedef char * String;

String stringConstructor(int length) {
	String newString = (String) malloc(sizeof(char) * length + 1);
	newString[length] = 0; //null terminate just in case
	return newString;
}

int stringSet(String this, char * string) {
	if (this==NULL) return NULL_PTR_ERROR;
	strcpy(this, string);
	return NO_ERROR;
}

int main(void) {

	int error_code =0;

	String a_string = stringConstructor(64);
	error_code = stringSet(a_string, "Hello world");
	if (error_code) {
		printf("Error - not a valid pointer\n");
	}
	else printf("%s\n", a_string);
}