建立一個void swap(int a,int b){}函式，賦值作為被調函式

void swap(int *p1,int *p2) {
	int tmp = *p1;
	int *p1 =  *p2;
	int *p2 =  tmp;
}
int main()
{
	int num1 = 10;
	int num2 = 20;
	printf("請輸入num1,num2");
	scanf(&num1, &num2);
	int num1 = &p1;
	int num2 = &p2;
	swap( num1,  num2)
		printf("輸出num1,num2");
}
 

不建立臨時變數，通過變數轉換實現變數內容的交換

int main() {
	int num1, num2;
	printf("請輸入連個數")；
		int num1 = num1 + num2;
	int num2 = num1 - num2;
	int num1 = num1 - num2;
	printf("請輸出兩個數\n");
	scanf("&num1,&num2");
	system("pause");
	return  0;

}

通過位運算實現，變數內容的交換

int main()
{
	int a, b;
	scanf_s("%d%d", &a, &b);
	a = a ^ b;
	b = a ^ b;
	a = b ^ a;
	printf("a=%d\n", a);
	printf("b=%d\n", b);
	system("pause");
	return 0;
}