用c++二维数组玩点阵数字显示

　　近期在教学中讲了二维数组，给学生布置了一大堆的练习题。不愿意为这一批能够投身学习的学生再多加硬性的任务了，练习题目中有的是他们要体会的。但前一段时间还准备了一个好玩的程序，当作额外的阅读参考公布出来吧，不作为教学要求了。

　　临近期末，玩编程，但也要为着考试让让路了。

　　书归正题，二维数组可以用在很多很多的地方。一个典型应用，存储“字模”，即显示信息要用到的点阵数据。

　　例如，下面的二维数组定义了10个数字的字模（要是采用别的字体，这个数组中的数字变一下即可）：

char a[10][8]=
{
    {0x00,0x18,0x24,0x24,0x24,0x24,0x24,0x18}, //0
    {0x00,0x18,0x1c,0x18,0x18,0x18,0x18,0x18}, //1
    {0x00,0x1e,0x30,0x30,0x1c,0x06,0x06,0x3e}, //2
    {0x00,0x1e,0x30,0x30,0x1c,0x30,0x30,0x1e}, //3
    {0x00,0x30,0x38,0x34,0x32,0x3e,0x30,0x30}, //4
    {0x00,0x1e,0x02,0x1e,0x30,0x30,0x30,0x1e}, //5
    {0x00,0x1c,0x06,0x1e,0x36,0x36,0x36,0x1c}, //6
    {0x00,0x3f,0x30,0x18,0x18,0x0c,0x0c,0x0c}, //7
    {0x00,0x1c,0x36,0x36,0x1c,0x36,0x36,0x1c}, //8
    {0x00,0x1c,0x36,0x36,0x36,0x3c,0x30,0x1c}, //9
};

　　以数字3对应的数据a[3]（{0x00,0x1e,0x30,0x30,0x1c,0x30,0x30,0x1e}, //3）为例，包括有8个十六进制的数，每行一个十六进制数，并且换成二进制的表示，会是什么样的呢？

　　是这样的：

00000000  //0x00
00011110  //0x1e
00110000  //0x30
00110000  //0x30
00011100  //0x1c
00110000  //0x30
00110000  //0x30
00011110  //0x1e

　　是的，我们就是要借着这个二维数组，玩点阵数字的显示。

【程序1】输入一个0-9之间的数字，用点阵的形式输出

#include <iostream>
using namespace std;
char a[10][8]=
{
    {0x00,0x18,0x24,0x24,0x24,0x24,0x24,0x18}, //0
    {0x00,0x18,0x1c,0x18,0x18,0x18,0x18,0x18}, //1
    {0x00,0x1e,0x30,0x30,0x1c,0x06,0x06,0x3e}, //2
    {0x00,0x1e,0x30,0x30,0x1c,0x30,0x30,0x1e}, //3
    {0x00,0x30,0x38,0x34,0x32,0x3e,0x30,0x30}, //4
    {0x00,0x1e,0x02,0x1e,0x30,0x30,0x30,0x1e}, //5
    {0x00,0x1c,0x06,0x1e,0x36,0x36,0x36,0x1c}, //6
    {0x00,0x3f,0x30,0x18,0x18,0x0c,0x0c,0x0c}, //7
    {0x00,0x1c,0x36,0x36,0x1c,0x36,0x36,0x1c}, //8
    {0x00,0x1c,0x36,0x36,0x36,0x3c,0x30,0x1c}, //9
};
int main()
{
    int n=0,i,j,x;
    int b[8];   //用于将字模中需要的某一行数据以二进制形式保存下来 
    cin>>n;
    for(i=0; i<8; i++)
    {
        x=a[n][i];  //a[n][i]，取要显示的数字n对应字模中的第i个数据x，这是要在每i行显示  
        for(j=0; j<8; j++)  //这个循环找出x以二进制的形式，保存在b数组中
        {
            b[j]=x%2;
            x=x/2;
        }   //注意b中放的数据是x的倒序，例0x30对应的二进制是00110000，b中存入的却是00001100  
        for(j=0; j<8; j++)  //输出b，为1输出*(你可以设置别的符号)，为0是空格，当然字型不会是反的了
        {
            if(b[j]%2)
                cout<<'*';
            else
                cout<<' ';
        }
        cout<<endl;
    }
    return 0;
}

　　上面程序中的数组b并不是必须的，可以一边算一边输出。于是main函数可以如下：

int main()
{
    int n=0,i,j,x;
    cin>>n;
    for(i=0; i<8; i++)
    {
        x=a[n][i];
        for(j=0; j<8; j++)
        {
            if(x%2)
                cout<<'*';
            else
                cout<<' ';
            x=x/2;
        }
        cout<<endl;
    }
    return 0;
}

【程序2】输入任意整数，用点阵形式输出 

#include <iostream>
using namespace std;
char a[10][8]=
{
    {0x00,0x18,0x24,0x24,0x24,0x24,0x24,0x18}, //0
    {0x00,0x18,0x1c,0x18,0x18,0x18,0x18,0x18}, //1
    {0x00,0x1e,0x30,0x30,0x1c,0x06,0x06,0x3e}, //2
    {0x00,0x1e,0x30,0x30,0x1c,0x30,0x30,0x1e}, //3
    {0x00,0x30,0x38,0x34,0x32,0x3e,0x30,0x30}, //4
    {0x00,0x1e,0x02,0x1e,0x30,0x30,0x30,0x1e}, //5
    {0x00,0x1c,0x06,0x1e,0x36,0x36,0x36,0x1c}, //6
    {0x00,0x3f,0x30,0x18,0x18,0x0c,0x0c,0x0c}, //7
    {0x00,0x1c,0x36,0x36,0x1c,0x36,0x36,0x1c}, //8
    {0x00,0x1c,0x36,0x36,0x36,0x3c,0x30,0x1c}, //9
};
int main()
{
    int n=0,i,j,k,m,x;
    int c[8];
    cin>>n;
    for(k=0; n&&k<8; k++)   //c数组将分离出n中的各位数，不过是倒着的，例n=123，c中保存3 2 1
    {
        c[k]=n%10;
        n/=10;
    }  //循环结束，将由k记住n是几位数，此处限最多8位数
    
    for(i=0; i<8; i++)   //一共要显示8行，不是依次显示k个数字，而是依次显示k个数字中对应的每一行
    {
        for(m=k-1; m>=0; m--)  //要显示n=123, c中是倒着保存各位数的，所以m由大到小
        {

            x=a[c[m]][i];     //现在要显示的数字是c[m]，所以取a数组中的第c[m]行，第i列数据
            for(j=0; j<8; j++)
            {
                if(x%2)
                    cout<<'*';
                else
                    cout<<' ';
                x=x/2;
            }
        }
        cout<<endl;
    }
    return 0;
}