C语言函数参数详解之实际参数(实参)&形式参数(形参)详解

#include <stdio.h>
int add(int x, int y)
{
	return x + y;
}
int main()
{
	int a = 20;
	int b = 30;
	int ret1 = add(20, 30);
	printf("%d\n", ret1);
	int ret2 = add(a, b);
	printf("%d\n", ret2);
	int ret3 = add(a + b, a - b);
	printf("%d\n", ret3);
	int ret4 = add(add(2, 3), 5);
	printf("%d\n", ret4);
	return 0;
}

#include <stdio.h>
int add(int x, int y)
{
	return x + y;
}
int main()
{
	int a = 20;
	int b = 30;
	//printf("%d %d", x, y);
	int ret1 = add(20, 30);
	printf("%d\n", ret1);
	int ret2 = add(a, b);
	printf("%d\n", ret2);
	int ret3 = add(a + b, a - b);
	printf("%d\n", ret3);
	int ret4 = add(add(2, 3), 5);
	printf("%d\n", ret4);
	return 0;
}

#include <stdio.h>
//实现成函数，但是不能完成任务
void Swap1(int x, int y) {
	int tmp = 0;
	tmp = x;
	x = y;
	y = tmp;
}
int main()
{
	int num1 = 1;
	int num2 = 2;
	Swap1(num1, num2);
	printf("Swap1::num1 = %d num2 = %d\n", num1, num2);
	return 0;
}

#include <stdio.h>
//正确的版本
void Swap2(int* px, int* py) {
	int tmp = 0;
	tmp = *px;
	*px = *py;
	*py = tmp;
}
int main()
{
	int num1 = 1;
	int num2 = 2;
	Swap2(&num1, &num2);
	printf("Swap2::num1 = %d num2 = %d\n", num1, num2);
	return 0;
}