蛇形矩阵

#include <stdio.h>
int main()
{
        int a[23][19]={0};                        
        int step[4][2]={{1,0},{0,1},{-1,0},{0,-1}};
        int m,n;      
        int x=0,y=0;
        int dir=0;   
        int t=0;     
        scanf("%d%d",&m,&n);
        while(t<m*n)         
        {
                a[x][y]=++t;     
                switch(dir)      
                {
                case 0:
                        if(x+1==m || a[x+1][y])dir=1;  
                        break;
                case 1:
                        if(y+1==n || a[x][y+1])dir=2;
                        break;
                case 2:
                        if(x-1<0 || a[x-1][y])dir=3;
                        break;
                case 3:
                        if(y-1<0 || a[x][y-1])dir=0;
                }
                x+=step[dir][0];               
                y+=step[dir][1];
        }
        for(x=0;x<m;x++)
        {
                for(y=0;y<n;y++)
                        printf("%4d",a[x][y]);
                printf("\n");
        }
        return 0;
}

#include <stdio.h>
void right (int a);
void down(int a);
void left(int a);
void up(int a);
int a[30][30], i, j, k,l,n,m,x,y,o,p;

 main()
{
    while (scanf("%d%d", &n, &m) != EOF)
    {
        x = n;
        y = m;//用以判断是否结束及输出
        o = n;
        p = m;//用以计算赋值个数
        i = 1;//用以赋值
        j =0 ;
        k = 0;//二维数组下标
        right(i);//从right开始即可
    }
}
void right(int i)
{
    if (i <= x * y)
    {
        for (l = 0; l < m; l++, k++, i++) a[j][k] = i;
        m -= 2;   //下次用right时赋值个数将减少两个
        k -= 1;   //循环结束后，k多加了一个1，减回来
        j += 1;   //下个被赋值的数为本次赋值的最后一个数的左边第一个
        down(i);   //之后函数的操作类似，就不注释了
    }
    else
        for (i = 0; i < x; i++)
        {
            for (j = 0; j < y; j++)
            {
                printf("%2d", a[i][j]);
                if (j != y - 1) printf(" ");
            }
            printf("\n");
        }

        
}
void down(int i)
{
    if (i <= x * y)
    {
        for (l = 0; l < n-1; l++, j++, i++) a[j][k] = i;
        n -= 2;
        j -= 1;
        k -= 1;
        left(i);
    }
    else
        for (i = 0; i < x; i++)
        {
            for (j = 0; j < y; j++)
            {
            
                printf("%2d", a[i][j]);
                if (j != y - 1) printf(" ");
            }
            printf("\n");
        }

}
void left(int i)
{
    if (i <= x * y)
    {
        for ( l = 0; l < p-1; l++, k--, i++) a[j][k] = i;
        p -= 2;
        k += 1;
        j -= 1;
        up(i);
    }
    else
        for (i = 0; i < x; i++)
        {
            for (j = 0; j < y; j++)
            {
                printf("%2d", a[i][j]);
                if (j != y - 1) printf(" ");
            }
            printf("\n");
        }

}
void up(int i)
{
    if (i <= x * y)
    {
        for ( l = 0; l < o-2; l++, j--, i++) a[j][k] = i;
        o-= 2;
        j += 1;
        k += 1;
        right(i);
    }
    else
        for (i = 0; i < x; i++)
        {
            for (j = 0; j < y; j++)
            {
                printf("%2d", a[i][j]);
                if (j != y - 1) printf(" ");
            }
            printf("\n");
        }

}