一道c++面试题 输入一个维度，逆时针打印出一个指定的矩阵

题目：逆时针打印矩阵元素

#include <stdio.h>
#include <malloc.h>

int main()
{
    int dimension;
    int *p;
    int startx, starty, endx, endy;
    int i, j, value = 0;
    
    printf("Please input dimension:");
    scanf("%d", &dimension);
    p = (int *)malloc(sizeof(int)*dimension*dimension);
    startx = 0;
    starty = 0;
    endx = dimension - 1;
    endy = dimension - 1;
    
    while(startx <= endx)
    {
        if(startx == endx) //只剩一个点需要赋值
        {
            p[endy*dimension+endx] = value++;
            break;
        }
        for(i = starty, j = startx; i <= endy; i++) //从上到下
        {
            p[i*dimension+j] = value ++;
        }
        
        for(i-=1, j = startx+1; j <= endx; j++) //从左到右, i在从上到下的输入中已经超出了矩阵范围，所以需要减1
        {
            p[i*dimension+j] = value++;
        }
        
        for(j-=1, i -= 1; i >= starty; i--) //从下到上
        {
            p[i*dimension+j] = value++;
        }
        
        for(i+=1, j -= 1; j > starty; j--) //从右到左
        {
            p[i*dimension+j] = value++;
        }
        
        startx ++;
        starty ++;
        endx --;
        endy --;
    }
    
    for(i = 0; i < dimension*dimension; i++)
    {
        if(0 == i%dimension)
            printf("\n");
        printf("%3d ", p[i]);
    }
    printf("\n\n");
    
    return 0;    
}

运行效果如下：

 

本文主要参考：http://blog.csdn.net/laoniu_c/article/details/38085767