数字菱形，由双层金字塔变形而来

#include<stdio.h>
int main()
{
    int i,j,n,m;
    scanf("%d",&n);
    for (i=1;i<=n;i++)  
    {
        for (j=1;j<=n-i;j++) 
            printf(" ");
        for(j=1;j<=2*i-1;j++)
            printf("%d",i);
        printf("\n");  
    }
    for (i=1;i<=n-1;i++)  
    {
        for (j=1;j<=i;j++) 
            printf(" ");
        for(j=1;j<=2*(n-i)-1;j++)
            printf("%d",n-i);
        printf("\n");  
    }
    return 0;
}