find the determinant of a matrix

[DANNY123]

I use Laplas to find the determinant, but the result is always 0.
my code:

#include <iostream>
#define N 100
int P[N][N];
using namespace std;


void determinant(int M[][N])
{ int n;
int det;
int A[N];
int B[N];
memset(A,0,sizeof(A));
memset(B,0,sizeof(B));

static int t=0;
static int f=0;
static int LHS=0;
static int RHS=0;
cout<<"please input the rows of the elements"<<endl;
cin>>n;
for(int a=0;a<n;a++)
 for(int b=0;b<n;b++)
   P[a][b]=(a+b)%3;
   


cout<<"please input the elements"<<endl;
for(int i=0;i<n;i++)
 for(int j=0;j<n;j++)
      cin>>M[i][j];

for(int i=0;i<n;i++)
{
do{ 

int y=P[i][t++];
A[i]*=M[t++][y];

}
while(t<n);
}    


for(int i=n-1;i>=0;i--)
{
do{ 

int y=P[i][f++];
B[i]*=M[f++][y];

}
while(f<n);
}   
for(int i=0;i<n;i++)
{LHS+=A[i];
}
for(int j=0;j<n;j++)
{RHS+=B[j];
}
det=LHS-RHS;

cout<<"The determinant is"<<det;

 cout<<endl;
}

int main()
{    int M[N][N];
    determinant(M);
    
    system("pause");
    return 0;
}

[ne555]

_ Indent your code
_ Modularize
_ Duck debug (especially lines 12,13,37,49,55,58)
_ Don't "optimize"

[DANNY123]

Can someone give some correction?

[vlad from moscow]

For example instead of

int A[N];
int B[N];
memset(A,0,sizeof(A));
memset(B,0,sizeof(B));

you could write

int A[N] = {};
int B[N] = {};

:)

[DANNY123]

I corrected so, but it still have bug

[vlad from moscow]

Sorry but i do not understand what your function does and have no any desire to investigate such a bad code.

Good luck!