C 语言实例 - 交换两个数的值

实例

#include <stdio.h>

int main()
{
      double firstNumber, secondNumber, temporaryVariable;
 
      printf("输入第一个数字: ");
      scanf("%lf", &firstNumber);
 
      printf("输入第二个数字: ");
      scanf("%lf",&secondNumber);
 
      /* 将第一个数的值赋值给 temporaryVariable */
      temporaryVariable = firstNumber;
 
      /* 第二个数的值赋值给 firstNumber */
      firstNumber = secondNumber;
 
      /* 将 temporaryVariable 赋值给 secondNumber */
      secondNumber = temporaryVariable;
 
      printf("\n交换后, firstNumber = %.2lf\n", firstNumber);
      printf("交换后, secondNumber = %.2lf", secondNumber);
 
      return 0;
}

输入第一个数字: 1
输入第二个数字: 2

交换后, firstNumber = 2.00
交换后, secondNumber = 1.00

实例

#include <stdio.h>

int main() {
   int a, b;
 
   a = 11;
   b = 99;
 
   printf("交换之前 - \n a = %d, b = %d \n\n", a, b);
 
   a = a + b;  /* ( 11 + 99 = 110)  此时 a 的变量为两数之和，b 未改变 */
   b = a - b;  /* ( 110 - 99 = 11) */
   a = a - b;  /* ( 110 - 11 = 99) */
 
   printf("交换后 - \n a = %d, b = %d \n", a, b);
}

交换之前 - 
 a = 11, b = 99 

交换后 - 
 a = 99, b = 11