How to Swap Two Int-type Integers

最新推荐文章于 2025-06-05 14:48:33 发布

原创最新推荐文章于 2025-06-05 14:48:33 发布 · 916 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#exchange #input #methods #variables #function #c

C/C++ 专栏收录该内容

194 篇文章

订阅专栏

本文介绍了使用C语言实现两个整数变量交换的不同方法。包括使用临时变量的经典方式，利用算术运算避免临时变量的方法，以及宏定义实现的指针无关交换等。每种方法都附带了代码示例。

I remember the time just learning C language, in general, there will be an example in some textbooks which asks us to write a function to swap two int-type integers. As we know, there are many ways to achieve this requirement. There are some common methods and also some skillful approaches. As a review, some of the methods described as below:

[Approach 1]

#include <stdio.h> /* * we use a variable named temp to complete an exchange */ void swap1(int *x,int *y) { int temp; temp=*x; *x=*y; *y=temp; } void swap2(int &x,int &y) { int temp; temp=x; x=y; y=temp; } void main() { int a=0,b=0; int *pa=&a,*pb=&b; printf("input a and b:/n"); scanf("%d%d",&a,&b); printf("a=%d/tb=%d/n",a,b); //invoke our function swap1(pa,pb); // ok,use pointer //swap1(&a,&b); // ok,use pointer //swap2(a,b); // ok,use reference printf("a=%d/tb=%d/n",a,b); }

[Approach 2]

#include <stdio.h> int a=0,b=0; // use global variable /* * we use two global variables and a temp variable to complete an exchange */ void swap(int ,int ) { int temp; temp=a; a=b; b=temp; } void main() { printf("input a and b:/n"); scanf("%d%d",&a,&b); printf("a=%d/tb=%d/n",a,b); //invoke our function swap(a,b); // ok,use global variable printf("a=%d/tb=%d/n",a,b); }

[Approach 3]

#include <stdio.h> /* * we do not use a temp variable to complete an exchange */ void swap1(int *x,int *y) { *x+=*y; *y=*x-*y; *x=*x-*y; } void swap2(int &x,int &y) { x+=y; y=x-y; x=x-y; } void main() { int a=0,b=0; int *pa=&a,*pb=&b; printf("input a and b:/n"); scanf("%d%d",&a,&b); printf("a=%d/tb=%d/n",a,b); //invoke our function swap1(pa,pb); // ok,use pointer //swap1(&a,&b); // ok,use pointer //swap2(a,b); // ok,use reference printf("a=%d/tb=%d/n",a,b); }

[Approach 4]

#include <stdio.h> /* * we use macro to complete an exchange without using pointer */ #define SWAP(x,y) do {/ (x) ^= (y);/ (y) ^= (x);/ (x) ^= (y);/ } while(0) void main() { int a=0,b=0; printf("input a and b:/n"); scanf("%d%d",&a,&b); printf("a=%d/tb=%d/n",a,b); //invoke our function SWAP(a,b); // ok,use macro without using pointer(Note!don't use like this: SWAP(x,x) otherwise it will get 0 not x) printf("a=%d/tb=%d/n",a,b); }