算术运算符

二元运算: +,-,*,/,%(取模或求余)

一元运算符: ++num,--num,num++,num--

int num1 = 10;

int num2= ++num1+num1--;

printf("num2=%d",num2);//22

printf("num1=%d",num1);//10

表达式	如何计算	结果 (num1=5)
num2 = ++num1;	num1 = num1 + 1; num2 = num1;	num2 = 6; num1 = 6;
num2 = num1++;	num2 = num1; num1 = num1 + 1;	num2 = 5; num1 = 6;
num2 = --num1;	num1 = num1 - 1; num2 = num1;	num2 = 4; num1 = 4;
num2 = num1--;	num2 = num1; num1 = num1 - 1;	num2 = 5; num1 = 4;

通过中间变量实现变量交换:

   int num1,num2;

   int temp;//中间变量

   printf("请输入的num1的值");

   scanf("%d",&num1);

   printf("请输入的num2的值");

   scanf("%d",&num2);

   printf("交换前num1=%d,num2=%d ",num1,num2);

   temp=num1;

   num1=num2;

   num2=temp;//通过中间变量实现交换

   printf("交换后num1=%d,num2=%d ",num1,num2);