Find a Inverse of a Matrix.

int i, j;

void display( int, int, float mat[10][10],float mat1[10][10]);
void input( int, int, float mat[10][10],float mat1[10][10]);
Inverse_Mat(int , int, float mat[10][10],float mat1[10][10]);
void swap(int, int, int, float mat[10][10],float mat1[10][10]);

/* This function exchange two rows of a matrix */

void swap( int row1,int row2, int col, float mat[10][10],float mat1[10][10])
{
for( i = 0; i < col; i++)
{
float temp = mat[row1][i];
mat[row1][i] = mat[row2][i];
mat[row2][i] = temp;

temp = mat1[row1][i];
mat1[row1][i] = mat1[row2][i];
mat1[row2][i] = temp;

}
}

/* This function find inverse of matrix */

int Inverse_Mat(int row1, int col1, float mat[10][10],float mat1[10][10])
{
int singular = 0;
int r, c;
for(r = 0;( r < row1)&& !singular; r++)
{

if( mat[r][r] ) /* Diagonal element is not zero */
for(c = 0; c < col1; c++)

if( c == r)
{

/* Make all the elements above and below the current principal
diagonal element zero */

float ratio = mat[r][r];
for( i = 0; i < col1; i++)
{
mat[r][i] /= ratio ;
mat1[r][i] /= ratio;
}
}
else
{
float ratio = mat[c][r] / mat[r][r];
for( i = 0; i < col1; i++)
{
mat[c][i] -= ratio * mat[r][i];
mat1[c][i] -= ratio * mat1[r][i];
}
}

else
{
/* If principal diagonal element is zero */
singular = 1;

for(c = (r+1); (c < col1) && singular; ++c)

if(mat[c][r])
{
singular = 0;
/* Find non zero elements in the same column */
swap(r,c,col1, mat, mat1);
--r;
}

}
}
return(!singular);
}

/* To print output this is used */

void display( int row, int col, float mat[10][10],float mat1[10][10])
{
printf("\n");
/* Output of inverse Matrix */
for( i = 0; i < row; i++)
{
for( j = 0; j < col; j++)
{
printf(" %f", mat1[i][j]);
}
printf("\n");
}

}

/* input function */

void input( int row, int col, float mat[10][10],float mat1[10][10])
{
for( i = 0 ; i< row; i++)
{
for( j = 0 ; j
{
printf("Input Value for: %d: %d: ", i+1, j+1);
scanf("%f", &mat[i][j]);
mat1[i][j] = 0;
}
mat1[i][i] = 1;
}
printf("\n Entered Matrix is as follows:\n");
for( i = 0; i < row; i++)
{
for( j = 0; j < col; j++)
{
printf(" %f", mat[i][j]);
}
printf("\n");
}
}


/* main function */


void main()
{

int R, C;
float mat[10][10];
float mat1[10][10];
printf("\n Input number of rows:");
scanf("%d", &R);
printf(" Input number of cols:");
scanf("%d", &C);
input(R,C, mat, mat1);

Inverse_Mat(R,C, mat, mat1);
printf("\n Inverse of above matrix is as follows:\n ");
display(R,C, mat, mat1);