#include <stdio.h>#define N 30static int val = 10;int arr[N][N];void print_row(int row_cur, int col_start, int col_end, int left_to_right){    int col_cur = col_start;    if( col_start < 0 || col_end < 0) return;    if( left_to_right){        while(col_cur < col_end){            printf("%d ", arr[row_cur][col_cur]);            //scanf("%d", &arr[row_cur][col_cur]);            arr[row_cur][col_cur] = val++;            ++col_cur;        }    }    else{        while(col_cur > col_end){            printf("%d ", arr[row_cur][col_cur]);                        arr[row_cur][col_cur] = val++;            --col_cur;        }    }}void print_col(int col_cur, int row_start, int row_end, int up_to_bottom){    int row_cur = row_start;    if(row_start < 0 || row_end < 0 ) return;    if(up_to_bottom){        while(row_cur < row_end){            printf("%d ", arr[row_cur][col_cur]);            //scanf("%d", &arr[row_cur][col_cur]);            arr[row_cur][col_cur] = val++;            ++row_cur;        }    }    else{        while(row_cur > row_end){            printf("%d ", arr[row_cur][col_cur]);            //scanf("%d", &arr[row_cur][col_cur]);            arr[row_cur][col_cur] = val++;            --row_cur;        }    }}void read_matrix(int row_start, int row_end, int col_start, int col_end){    if(row_start > row_end|| col_start > col_end)        return;    if(row_start == row_end || col_start == col_end)    {        printf("%d ", arr[row_start][col_start]);        //scanf("%d", &arr[row_start][col_start]);        arr[row_start][col_start] = val++;        return;    }    int i = row_start;    int j = col_start;    int i_end = row_end;    int j_end = col_end;        print_row(i,       j,        j_end,   1);        print_col(N-j-1,   i,        i_end,     1);        print_row(N-i-1,   j_end,    j,    0);        print_col(j,       i_end,    i, 0);    read_matrix(row_start+1,   row_end-1, col_start+1, col_end-1);}void printf_(){    int i, j ;    i = 0, j = 0;    while(i < N){        while(j < N){            printf("%d ", arr[i][j]);            ++j;        }        printf("\n");        ++i;        j = 0;    }}int main(void){    memset(arr, N*N,0);    read_matrix(0, N-1, 0, N-1);    getchar();    printf_();}

运行结果 ：