C++ program for finding determinant value and Inverse of a Matrix

 C++ program for finding determinant value and Inverse of a Matrix (3x3)

-Dinesh Kumar E

This is a simple C++ program to find Determinant value and inverse of matrix.

Code:

#include<iostream>

#include<iomanip>

using namespace std;

int m[10],j,ch,det,i[10];

int main()

{

cout<<"To find Inverse of matrix"<<endl<<"Enter the correct option"<<endl<<"1 for  2x2 matrix\n2 for 3x3 matrix"<<endl;cin>>ch

switch(ch)

case 1:

{for(j=0;j<9;j++)

{

cout<<"Enter no "<<j+1<<" element ";

cin>>m[j];

}

det=((m[4]*m[8]-m[7]*m[5])*m[0])-((m[3]*m[8]-m[6]*m[5])*m[1])+((m[3]*m[7]-m[6]*m[4])*m[2]);

if(det!=0)

{

i[0]=1*(m[4]*m[8]-m[7]*m[5]);

i[1]=-1*(m[3]*m[8]-m[6]*m[5]);

i[2]=1*(m[3]*m[7]-m[6]*m[4]);

i[3]=-1*(m[1]*m[8]-m[7]*m[2]);

i[4]=1*(m[0]*m[8]-m[6]*m[2]);

i[5]=-1*(m[0]*m[7]-m[6]*m[1]);

i[6]=1*(m[1]*m[5]-m[4]*m[2]);

i[7]=-*(m[0]*m[4]-m[3]*m[1]);

cout<<1*(m[0]*m[5]-m[3]*m[2]);

i[8]=1"\n\nThe inverse of entered matrix is :"<<endl;

cout<<"| "<<i[0]<<" "<<i[3]<<" "<<i[6]<<"|";

cout<<setw(8)<<" * "<<" 1/"<<det<<endl;

cout<<"| "<<i[1]<<" "<<i[4]<<" "<<i[7]<<"|"<<endl;

cout<<"| "<<i[2]<<" "<<i[5]<<" "<<i[8]<<"|"<<endl;

}

else

cout<<"\n\nThis matrix don't have inverse because its determine vale is "<<det;}

case 2:

for(j=0;j<4;j++)

{

cout<<"Enter no "<<j+1<<" element ";

cin>>m[j];

}

}