How to create Spiral matrix in C++

Hope you all know about spiral matrices. Here the given c++ program will gives spiral matrix as output. This is commonly asked in programming rounds of many interviews.

input : 4;
output is :
1      2     3     4 
12   13   14    5 
11   16   15    6 
10    9    8      7

input : 5;
output :
1       2     3     4    5 
16   17   18   19    6 
15   24   25   20    7 
14   23   22   21    8 
13   12   11   10    9

#include <iostream>
#include <iomanip>

#define SIZE 4

int main()
{
    int matrix[SIZE][SIZE] = {0};
    int count = 0;
    
    int up = 0;
    int down = SIZE - 1;
    while(count != SIZE * SIZE)
    {
        for(int i = 0; i < SIZE; ++i)
        {
            if(matrix[up][i] == 0)
            {
                matrix[up][i] = ++count;
            }
        }
        for(int i = 0; i < SIZE; ++i)
        {
            if(matrix[i][down] == 0)
            {
                matrix[i][down] = ++count;
            }

        }
        for(int i = SIZE - 1; i >= 0; --i)
        {
            if(matrix[down][i] == 0)
            {
                matrix[down][i] = ++count;
            }

        }
        for(int i = SIZE - 1; i >= 0; --i)
        {
            if(matrix[i][up] == 0)
            {
                matrix[i][up] = ++count;
            }

        }
        ++up;
        --down;
    }
    
    std::cout << "The Spiral Matrix of number : " << SIZE << std::endl;
    for(int i = 0; i < SIZE; ++i)
    {
        for(int j = 0; j < SIZE; ++j)
        {
            std::cout << std::setw(4) << matrix[i][j] << " ";
        }
        std::cout << std::endl;
    } 
}

This is one of the method for creating spiral matrix. This may not be an efficient method you can also search for others methods.