判断大小端

使用强制类型转换

#include <stdio.h>
int main()
{
	int num = 1;
	char* ch = (char*)(&num);
	if(*ch == 1)
		printf("小端\n");
	else
		printf("大端\n");
	return 0;
}

使用联合体

#include <stdio.h>
union um {
	int i;
	char q;
};
int main()
{
	union um un;
	un.i = 1;
	if (un.q == 1)
		printf("小端\n");
	else
		printf("大端\n");
	return 0;
}