#include <stdio.h>

struct Test {
	char str;
};

void change1(struct Test *t){
	t->str = 'B';
}

void change2(struct Test *t){
	static struct Test tmp = { 'A' };
	*t = tmp;
	t->str = 'B';
}

int main(void) {
	struct Test t1 = { 'A' };
	change1(&t1);
	printf("%c\n", t1);

	struct Test t2 = { 'A' };
	change1(&t2);
	printf("%c\n", t2);

	return 0;
}