[C++]函数参数浅析

Date:
2014-1-9

Summary:

函数参数相关记录

Contents:
1.形参实参

形参:用于接收值的变量被称为形参

实参:传递给函数的值被称为实参

2.函数的参数传递之后2种

a).值传递.将实参的值拷贝之后，传递给形参（如果是指针，则拷贝指针的值，传递给形参）

b).引用传递.如果形参是引用，则形参被绑定到了对应的实参上

Notes:

1.使用引用作为形参，尽量避免拷贝

2.函数参数，非引用传递，则为拷贝值传递

 

EX:

    //
    //  main.cpp
    //  Cpp_All_Test
    //
    //  Created by StephenLee on 1/1/14.
    //  Copyright (c) 2014 StephenLee. All rights reserved.
    //

void mySwap(int* pNum1,int* pNum2)
{
    int temp = (*pNum1);
    (*pNum1) = (*pNum2);
    (*pNum2) = temp;
}

void mySwap(int& num1,int& num2)
{
    int temp = num1;
    num1 = num2;
    num2 = temp;
}


    int nNum1 = 10;
    int nNum2 = 20;
    cout << "nNum1:" << nNum1 << "
nNum2:" << nNum2 << endl;
    mySwap(&nNum1,&nNum2);
    
    cout << "after mySwap 
nNum1:" << nNum1 << "
nNum2:" << nNum2 << endl;

    mySwap(nNum1,nNum2);
    cout << "after mySwap 
nNum1:" << nNum1 << "
nNum2:" << nNum2 << endl;

THE END