Go string in C

main.c

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

typedef struct {
	char *str;
	int len;
} string;

string appendString(string s1, string s2) {
	string r;
	r.len = s1.len + s2.len;
	r.str = malloc(sizeof(char) * r.len);
	memcpy(r.str, s1.str, sizeof(char) * s1.len);
	memcpy(r.str + sizeof(char) * s1.len, s2.str, sizeof(char) * s2.len);
	return r;
}

void sayHello(string name) {
	printf("Hello, %.*s\n", name.len, name.str);
}

void mutateString1(string s) {
	s.len = 10;
	s.str = malloc(sizeof(char) * s.len);
	memcpy(s.str, "John Titor", sizeof(char) * s.len);
}

void mutateString2(string *s) {
	s->len = 10;
	s->str = malloc(sizeof(char) * s->len);
	memcpy(s->str, "John Titor", sizeof(char) * s->len);
}

int main() {
	string myName;
	myName.len = 8;
	myName.str = malloc(sizeof(char) * myName.len);
	memcpy(myName.str, "acoshift", sizeof(char) * myName.len);

	sayHello(myName);
	mutateString1(myName);
	sayHello(myName);
	mutateString2(&myName);
	sayHello(myName);

	string n;
	n.len = 9;
	n.str = malloc(sizeof(char) * n.len);
	memcpy(n.str, " IBM 5100", sizeof(char) * n.len);

	string t = appendString(myName, n);
	sayHello(t);

	return 0;
}