学步园

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

//////////method first//////////////////
//直接用二维数组的形式
void fun(int a[3][4])
{
    for(int i=0; i<3; ++i)
    {
        for(int j=0; j<4; ++j)
        {
            cout<<"a["<<i<<"]["<<j<<"]="<<setw(3)<<a[i][j]<<"\t";
        }
        cout<<endl;
    }
}

/////////////method second//////////////
//用指向数组的指针
void fun1(int (*p)[4])
{
    for(int i=0; i<3; ++i)
    {
        for(int j=0; j<4; ++j)
        {
            cout<<"p["<<i<<"]["<<j<<"]="<<setw(3)<<p[i][j]<<"\t";
        }
        cout<<endl;
    }
}

///////////method third/////////////////
//形参采用指针，如int* p,而主函数进行特殊操作，使二维数组传值到函数里。
void fun2(int *p)
{
    for(int i=0; i<4; ++i)
    {
        cout<<"p["<<i<<"]="<<setw(3)<<p[i]<<"\t";
    }
    cout<<endl;
}
////////////method forth////////////////
//用指向指针的指针，如int** p,
void fun3(int **p)
{
    for(int i=0; i<3; ++i)
    {
        for(int j=0; j<4; ++j)
        {
            cout<<"p["<<i<<"]["<<j<<"] = "<<setw(5)<<p[i][j]<<"\t";
        }
        cout<<endl;
    }
}


int main(int argc,char* argv[])
{
    int a[3][4]= {0,1,2,3,4,5,6,7,8,9,10,11};
    fun(a);
    cout<<endl;
    fun1(a);
    cout<<endl;
    for(int i=0; i<3; ++i)
    {
        fun2(*(a+i));
    }
//      fun3(a);
//编译时发生错误。int [][]不能转换为int**
//error: cannot convert ‘int (*)[4]’ to ‘int**’ for argument ‘1’ to ‘void fun3(int**)’
////////////////////////////////////////
    int row=3, col=4;
/////////create the 2d dynamic array////
////////////////////////////////////////
    int **p=new int *[row];
    for(int i=0; i<row; ++i)
    {
//用p[i]指向第一个含有col个元素的数组///
        p[i]=new int[col];
//p[0]、p[1]、p[2]分别指向一个含有col个元素的数组，
    }
////////////////////////////////////////

    for(int i=0; i<row; ++i)
    {
        for(int j=0; j<col; ++j)
        {
            p[i][j]=i*j+j+99;
        }
    }

    cout<<"p="<<p<<"  sizeof(p)="<<sizeof(p)<<" *p = "<<*p<<endl;
    cout<<"p[0]="<<p[0]<<"\t"<<"*(p+0) = "<<*(p+0)<<endl;

    cout<<"p[1]="<<p[1]<<"\t"<<"*(p+1) = "<<*(p+1)<<endl;
    cout<<"p[2]="<<p[2]<<"\t"<<"*(p+2) = "<<*(p+2)<<endl;
    int b[2][5]= {0};
    cout<<"b="<<b<<"\t"<<"b[0]="<<b[0]<<endl;

    fun3(p);

////////////////////////////////////////
//////////删除自己申请的空间////////////
    for(int i=0; i<row; ++i)
    {
        delete []p[i];
        cout<<"delete p["<<i<<"]"<<"\t";
    }
    cout<<endl;
    delete []p;
    cout<<"delete p"<<endl;
////////////////////////////////////////
    cin.get();
//    return 0;

}
//
//[root@yutong array]# g++ -o twodimarraypara twodimarraypara.cpp
//[root@yutong array]# ./twodimarraypara 
//a[0][0]=  0   a[0][1]=  1     a[0][2]=  2     a[0][3]=  3     
//a[1][0]=  4   a[1][1]=  5     a[1][2]=  6     a[1][3]=  7     
//a[2][0]=  8   a[2][1]=  9     a[2][2]= 10     a[2][3]= 11     
//
//p[0][0]=  0   p[0][1]=  1     p[0][2]=  2     p[0][3]=  3     
//p[1][0]=  4   p[1][1]=  5     p[1][2]=  6     p[1][3]=  7     
//p[2][0]=  8   p[2][1]=  9     p[2][2]= 10     p[2][3]= 11     
//
//p[0]=  0      p[1]=  1        p[2]=  2        p[3]=  3        
//p[0]=  4      p[1]=  5        p[2]=  6        p[3]=  7        
//p[0]=  8      p[1]=  9        p[2]= 10        p[3]= 11        
//p=0x1adf010  sizeof(p)=8 *p = 0x1adf030
//p[0]=0x1adf030        *(p+0) = 0x1adf030
//p[1]=0x1adf050        *(p+1) = 0x1adf050
//p[2]=0x1adf070        *(p+2) = 0x1adf070
//b=0x7fff0c6e79f0      b[0]=0x7fff0c6e79f0
//p[0][0] =    99       p[0][1] =   100 p[0][2] =   101 p[0][3] =   102 
//p[1][0] =    99       p[1][1] =   101 p[1][2] =   103 p[1][3] =   105 
//p[2][0] =    99       p[2][1] =   102 p[2][2] =   105 p[2][3] =   108 
//delete p[0]   delete p[1]     delete p[2]     
//delete p
//