字符串的交换——3种实现

要知道，a[100]字符串的首地址与char *a 是不一样的，

a[100]字符串的首地址不是指针，char *a就是指针！！！

//swap(char *a,char *b)
#include<iostream>
#include<string.h>
using namespace std;

void swap(char *a,char *b)
{
    int al,bl,i;
    al=strlen(a)+1;
    bl=strlen(b)+1;
    if(al<bl)al=bl;

    int temp;
    for(i=0;i<al;i++)
    {
        
        temp=a[i];
        a[i]=b[i];
        b[i]=temp;
    }
}

void main()
{
    char ap[20]="hello!";
    char bp[20]="how are you!";
    
    swap(ap,bp);
    cout<<ap<<endl;
    cout<<bp<<endl;
}


//swap(char* *a,char* *b)
#include<iostream>
using namespace std;

void swap1(char* *a,char* *b)
{
    char *temp;
    temp=*a;
    *a=*b;
    *b=temp;
}

void main()
{
    char *ap="hello!";
    char *bp="how are you!";
    
    swap1(&ap,&bp);
    cout<<ap<<endl;
    cout<<bp<<endl;
}

//swap(char* &a,char* &b) 
#include<iostream>
using namespace std;

void swap1(char* &a,char* &b)
{
    char *temp;
    temp=a;
    a=b;
    b=temp;
}

void main()
{
    char *ap="hello!";
    char *bp="how are you!";
    
    swap1(ap,bp);
    cout<<ap<<endl;
    cout<<bp<<endl;
}