C++利用宏實現變量交換的三種方式

 

#include <iostream>

using namespace std;

//引入中間變量
#define SWAP1(a,b) {int tmp=a;a=b;b=tmp;} 

//算數技巧，須要考慮越界與否
#define SWAP2(a,b) {a=a+b;b=a-b;a=a-b;}

//位運算，不考慮越界
#define SWAP3(a,b) {a=a^b;b=a^b;a=a^b;}

int main()
{
    int a = 1,b = 2;
    SWAP1(a,b);
    cout << "引入中間變量：" << a << " " << b << endl;

    SWAP2(a,b);
    cout << "算數技巧：" << a << " " << b << endl;

    SWAP3(a,b);
    cout << "位運算：" << a << " " << b << endl;

    return 0;
}

 

 

做者：耑新新，發佈於  博客園

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