C++ 函数模板(十四)--template 泛型函数模板、通用函数、重载模板

#include <iostream>
#include <string>
using namespace std;

//函数模板,typename 等价于 class
template <typename AnyType>
void test(AnyType &a, AnyType &b) {
    
    auto c = a;
    a = b;
    b = c;
}


//重载模板
template <typename AnyType>
void test(AnyType &a,AnyType &b,AnyType &c) {
    c = a+b;
}

template <typename T>
void test(T *a,T *b,T *c) {  //传指针地址的实参方式，在析构函数时，c值的改变也对应改变外部参数
    *c = *a+*b;
}

template <typename T>  //c 是新创建的int变量，和外部参数值互不影响 ， ab是两种引用的表现方式
void test(T *a,T &b, int c) {
    
    auto to = *a;
    *a = b;
    b = to;
    c++;
}


template <typename AnyType2>
void test2(AnyType2 &a, AnyType2 &b) {
    
    auto c = b;
    b = a;
    a = c;
    
}


template <class T>
void test3(T &a, T &b) {
    auto c = a;
    a = b;
    b = c;
}



struct stdo {
    float fu;
    char cr[30];
};

//具体化显式模板
template <typename T>
void testss(stdo &a ,stdo &b){
    
    auto fu = a.fu;
    a.fu = b.fu;
    b.fu = fu;
}


template <int>
void ttsdf(int i,int b){
    
    cout << "f" << endl;
    
}


int main(int argc, const char * argv[]) {

    //概念:C++编译器实现了新增一项特性--函数模板,通用的函数描述;使用泛型定义函数
    
    int i = 10;
    int ii = 200;
    int iii = 100;

    string a = "aaa";
    string b = "bbbb";
    size_t tt = a.length();
    
    //利用泛型的函数模板交换两个整型值
    test(i,ii);
    cout << "交换两个整型值\n" << "i=" << i << endl << "ii=" << ii << endl;
    
    test(&i, &ii, &iii);
    cout << "重载\n" << "iii=" << iii << endl << "=" << ii << endl;
    
    test(&i, ii, iii);
    cout << "重载\n" << "iii=" << iii << endl << "i=" << i << endl << "ii=" << ii << endl;

    
    
    //利用泛型的函数模板交换两个字符串值
    test2(a,b);
    cout << "交换两个字符串值\n" << "a=" << a << endl << "b=" << b << endl;
    
    
    
    //显式模板,交换两个结构体中的元素
    cout.precision(2);  //保留小数点后两位
    cout.setf(ios::fixed, ios::floatfield);
    
    stdo sto = {999.234,"dsfsdf"};
    stdo sto2 = {110.45222,"aaaaaa"};

    testss<stdo>(sto,sto2);
    cout << "显式模板\n" << "sto.fu=" << sto.fu << endl << "sto2.fu=" << sto2.fu << endl;


    ttsdf<2>(10, 10);
    
    return 0;
}