# C++ Program to Find Inverse of a Given Matrix

• First, calculate the determinant of the matrix.
• Then calculate the adjoint of a given matrix. Adjoint can be obtained by taking the transpose of the cofactor matrix of a given square matrix.
• Finally, multiply 1/deteminant by adjoint to get inverse.

## C++ Program to Find Inverse of a Given Matrix

``````#include<iostream>
using namespace std;
int main(){
int mat[3][3], i, j;
float determinant = 0;
cout<<"Enter elements of matrix row wise:\n";
for(i = 0; i < 3; i++)
for(j = 0; j < 3; j++)
cin>>mat[i][j];

printf("\nGiven matrix is:");
for(i = 0; i < 3; i++){
cout<<"\n";

for(j = 0; j < 3; j++)
cout<<mat[i][j]<<"\t";
}

for(i = 0; i < 3; i++)
determinant = determinant + (mat[0][i] * (mat[1][(i+1)%3] * mat[2][(i+2)%3] - mat[1][(i+2)%3] * mat[2][(i+1)%3]));

cout<<"\n\ndeterminant: "<<determinant;

cout<<"\n\nInverse of matrix is: \n";
for(i = 0; i < 3; i++){
for(j = 0; j < 3; j++)
cout<<((mat[(j+1)%3][(i+1)%3] * mat[(j+2)%3][(i+2)%3]) - (mat[(j+1)%3][(i+2)%3] * mat[(j+2)%3][(i+1)%3]))/ determinant<<"\t";

cout<<"\n";
}

return 0;
}``````

Output Of Program

Enter elements of matrix row wise:
3
254
25
23
2
1
3
2
23

Given matrix is:
3 254 25
23 2 1
3 2 23

determinant: -132472

Inverse of matrix is:
-0.000332146 0.0437224 -0.00153995
0.00397065 4.52926e-005 -0.00431789
-0.000301951 -0.00570687 0.0440546

Categories C