魔方陣

#include <iostream>
using namespace std;

void main(){
    const int ms = 9;
    int M[ms][ms];
    int i, j;
    int r = 0, c = (int) (ms / 2);
    for(i = 0; i< ms;i++){
        for(j = 0; j< ms;j++){
            M[i][j] = 0;
        }
    }

    M[r][c] = 1;    
    for (int step = 2; step <= ms*ms; step++){
        r = (r - 1 + ms)  % ms; c = (c -1 + ms) % ms;
        if (M[r][c] != 0) {
            r = (r + 2) % ms;
            c = (c + 1) % ms;
        }
        M[r][c] = step;
    }

    for(i = 0; i< ms;i++){
        for(j = 0; j< ms;j++){
            if (M[i][j] < 10) cout << " "; //若是個位數，先輸出個空白…(若這個方陣裏的數字有大到3位數的話，要怎麼辦？
            cout << M[i][j] << " " ;
        }
        cout << endl;
    }
    cin >> i;    
}

動態記體配置版本

#include <iostream>
#include "stdio.h"

using namespace std;

int main(void){    
    int matrixSize ;
    cin >> matrixSize;

    int** Matrix; //宣告一個"指標的指標"，或"陣列的陣列"，就是2維陣列
    Matrix = (int **)malloc(matrixSize*sizeof(int)); //配置第一維整數陣列

    for (int i=0; i<matrixSize; i++){
        Matrix[i] = (int *)malloc(matrixSize*sizeof(int)); //配置第2維陣列
    }

    if (matrixSize%2 == 0 && matrixSize < 3) return -1; 

    for (int i = 0; i < matrixSize; i++){
        for(int j=0; j< matrixSize; j++){
         Matrix[i][j] = 0 ; //將陣列裏的每個元素初始為0
        }
    }

    int row  =0;
    int col = matrixSize / 2;
    Matrix[row][col] = 1;

    for (int stepper = 2; stepper <= matrixSize * matrixSize; stepper++){
        row = (row - 1 + matrixSize) % matrixSize;
        col = (col - 1 + matrixSize) % matrixSize;
        if (Matrix[row][col] != 0) {
            row = (row + 2) % matrixSize;
            col = (col + 1) % matrixSize;
        }
        Matrix[row][col] = stepper;
    }

    for (int i = 0; i < matrixSize; i++){
        for(int j=0; j< matrixSize; j++){

            printf("%4d ",  Matrix[i][j]) ;

        }
        cout << endl;
    }
}