/*
 * To find the determinant of a 3 X 3 matrix
 * @author-Karan Narain(karan@iitk.ac.in)
 *
*/

#include <stdio.h>
#include <math.h>
int main()
{
	int A[3][3],i,j,det=0;
	
	printf("Enter the 3 X 3 matrix\n");
	for(i=0;i<3;i++)
		for(j=0;j<3;j++)
			scanf("%d",&A[i][j]); 
	
	/*The direct way to do this is to simply calculate the determinant using constant index values,i.e.
	 * det=(A[0][0] * (A[1][1]*A[2][2]-A[2][1]*A[1][2])) - (A[0][1] * (A[1][0]*A[2][2]-A[2][0]*A[1][2])) + (A[0][2] * (A[1][0]*A[2][1]-A[2][0]*A[1][1]))
	 * This program calculates the determinant using i and j as indices in a for loop,instead of the above method
	 */
	//i should denote the first row.so set i=0
	i=0;
	for(j=0;j<3;j++)
	{
		if(j==0)
		{
			det=det+A[i][j]*(A[i+1][j+1]*A[i+2][j+2]-A[i+2][j+1]*A[i+1][j+2]);	
		}
		else if(j==1)
		{
			det=det-A[i][j]*(A[i+1][j-1]*A[i+2][j+1]-A[i+2][j-1]*A[i+1][j+1]);	
		}
		else
		{
			det=det+A[i][j]*(A[i+1][j-2]*A[i+2][j-1]-A[i+2][j-2]*A[i+1][j-1]);	
		}

	}	
        
	printf("The determinant is %d",det);
	return 0;

}