c++中有几种交换变量的方法

#include <iostream>
#include <string>
using namespace std;
void Swap(int& a,int& b)
{
    int c = a;
    a = b;
    b = c;
}
void Swap(double& a,double& b)
{
    double c = a;
    a = b;
    b = c;
}
void Swap(string& a,string& b)
{
    string c = a;
    a = b;
    b = c;
}

int main()

{
    int a = 0;
    int b = 1;
    Swap(a,b);
    cout << "a = "<< a << endl;
    cout << "b = "<< b << endl;
    double m = 2;
    double n = 3;
    Swap(m,n);
    cout << "m = "<< m << endl;
    cout << "n = "<< n << endl;
    string d = "yingli";
    string t = "zhang";
     Swap(d,t);
    cout << "d = "<< d << endl;
    cout << "t = "<< t << endl;

    return 0;

}

输出：

a = 1
b = 0
m = 3
n = 2
d = zhang
t = yingli

泛型编程

泛型编程的概念

不考虑数据类型的编程方式

函数模板

C++中的泛型编程

函数模板

一种特殊的函数可用不同类型进行调用

看起来和普通函数很相似，区别是类型可被参数化

函数模板的语法规则

template关键字用于生命开始进行泛型编程

typename关键字用于声明泛指类型

#include <iostream>

#include <string>



using namespace std;


template <typename T>

void Swap(T& a,T& b)
{
    T c = a;
    a = b;
    b = c;
}


int main()

{
    int a = 0;
    int b = 1;


    Swap(a,b);
    cout << "a = "<< a << endl;
    cout << "b = "<< b << endl;
    double m = 2;
    double n = 3;
    Swap(m,n);
    cout << "m = "<< m << endl;
    cout << "n = "<< n << endl;
    string d = "yingli";
    string t = "zhang";
     Swap(d,t);
    cout << "d = "<< d << endl;
    cout << "t = "<< t << endl;

    return 0;

}

输出：

5, 3, 2, 4, 1, 
1, 2, 3, 4, 5, 
Java, C++, Pascal, Ruby, Basic, 
Basic, C++, Java, Pascal, Ruby, 

a = 1
b = 0
m = 3
n = 2
d = zhang
t = yingli

例子：

#include <iostream>
#include <string>

using namespace std;

template < typename T >
void Swap(T& a, T& b)
{
    T c = a;
    a = b;
    b = c;
}

template < typename T >
void Sort(T a[], int len)
{
    for(int i=0; i<len; i++)
    {
        for(int j=i; j<len; j++)
        {
            if( a[i] > a[j] )
            {
                Swap(a[i], a[j]);
            }
        }
    }
}

template < typename T >
void Println(T a[], int len)
{
    for(int i=0; i<len; i++)
    {
        cout << a[i] << ", ";
    }
    
    cout << endl;
}

int main()
{
    int a[5] = {5, 3, 2, 4, 1};
    
    Println(a, 5);
    Sort(a, 5);
    Println(a, 5);
    
    string s[5] = {"Java", "C++", "Pascal", "Ruby", "Basic"};
    
    Println(s, 5);
    Sort(s, 5);
    Println(s, 5);
    
    return 0;
}

小结：