一个矩形外围为同一个数，并先内加一圈就加1，第一圈为1

例1111112221123211222111111#include <stdio.h>#define N 7void fun(int (*a)[N]){ int i,j,k,m;if(N%2==0) m=N/2 ;else m=N/2+1;for(i=0; i<m; i++) { for(j=i; j<N-i; j++)a[i][j]=a[N-i-1][j]=i+1;for(k=i+1; k<N-i; k++)a[k][i]=a[k][N-i-1]=i+1;}}void main(){ int x[N][N]={0},i,j;fun(x);printf("\nThe result is:\n");for(i=0; i<N; i++){ for(j=0; j<N; j++) printf("%3d",x[i][j]);printf("\n");}}