sizeof implemented as a macro

sizeof.c

#define sizeof(x) ((size_t)(((typeof(x)*)0)+1))

#include <stdio.h>

struct foo{
	char a,b,c,d,e;
};

int main(){
	printf("%zu\n", sizeof(int));
	printf("%zu\n", sizeof(int*));
	printf("%zu\n", sizeof(char));
	printf("%zu\n", sizeof(char*));
	printf("%zu\n", sizeof(&main));
	printf("%zu\n", sizeof(int[3]));
	printf("%zu\n", sizeof("Hello!"));
	printf("%zu\n", sizeof(struct foo));
}