917exercises2.c

#include <stdio.h>
#include <stdlib.h>
#define maxRow 99         //最大行数
int main() {
  int n,x,y;
  int count = 1;            //探索している数字。
  short **arr,*base_arr; //行列。
  printf("n = ");  
  while(scanf("%d", &n) != 1 || n < 3 || n > maxRow || n%2 == 0) {
    printf("#matrix must be at least 3 and at most %d and odd.\n",maxRow);
    while(getchar() != '\n') {}; 
    printf("n = ");
  }
  arr = malloc(sizeof(short *) * n);
  base_arr = malloc(sizeof(short) * n * n);
  for(y=0;y<n;y++) {
    arr[y] = base_arr + y * n;
    for(x=0;x<n;x++) {
      arr[y][x] = 0;
    }
  }
  y = 0;
  x = n/2;
  arr[y][x] = 1;
  count++;
  while(count <= n*n) {
    if(count%n == 1) {
      y++;
      if(y == n) y-= n;
    } else {
      y--;
      x++;
      if(x == n) x-= n;
      if(y == -1) y+= n;
    } 
    while(arr[y][x] != 0) {
      y++;
      if(y == n) y-= n;
    }
    arr[y][x] = count;
    count++;
  }
  for(y=0;y<n;y++) {
    for(x=0;x<n;x++) {
      printf("%4d",arr[y][x]);
    }
    puts("");
  }
  free(base_arr);
  free(arr);
  return 0;
}