\(\begin{array}{ccccc}1&2&3&4&5\\16&17&18&19&6\\15&24&25&20&7\\14&23&22&21&8\\13&12&11&10&9\end{array}\) 

Write a program that reads a number and displays the above pattern.

#include<stdio.h>
#include<conio.h>
#define SIZE 100

void main()
{
	int N, i, j;
	int grid[SIZE][SIZE];
	int left, top, counter;

	do{
		printf("Enter N: ");
		scanf("%d",&N);
	}while(N<=0 || N>SIZE);

	left = 0;
    	top = N - 1;
    	counter = 1;
	
	// at each iteration, we will fill
	// 1. the upper row (from left to right) -->
	// 2. the right column (from top to bottom)
	// 3. the lower row (from right to left) <--
	// 4. the left column (from bottom to top)
	// so basically, we will be looping N/2 times
	// we take into account where N is odd, we need 
	// to add one more iteration
    	for(i=1; i<=N/2+1; i++, left++, top--)
    	{
        	// 1. fill the upper row (from left to right) -->
        	for(j=left; j<=top; j++, counter++)
            		grid[left][j] = counter;

       		// 2. fill the right column (from top to bottom)
        	for(j=left+1; j<=top; j++, counter++)
            		grid[j][top] = counter;

        	// 3. fill the lower row (from right to left) <--
        	for(j=top-1; j>=left; j--, counter++)
            		grid[top][j] = counter;

       		// 4. fill the left column (from bottom to top)
        	for(j=top-1; j>=left+1; j--, counter++)
          		grid[j][left] = counter;
	}

    	for(i=0; i<N; i++)
	{
        	for(j=0; j<N; j++)
           		printf("%4d", grid[i][j]);
      	  	printf("\n");
	}


	getch();
}