matrix - How to solve n equation with Jacobi method by C++? -

this code should get

• number of equations (n)
• matrix a
• matrix b
• accuracy of answer (e)as input

and find answer of n equations jacobi method.

my code:

     #include <cstdlib>      #include <iostream>      #include <conio.h>      #include <math.h>  using namespace std; // dev software code using 'cin' instead 'scanf'  int main() {     int n,i,j,l=0;     cout<<"enter number of equations = ";     cin>>n;     double a[n-1][n-1],b[n-1][1],x[n-1][1],t[n-1][1],e,k;     cout<<"[a].[x]=[b]"<<endl;     cout<<"enter matrix a:"<<endl;     for(i=0;i<n;i++)     for(j=0;j<n;j++)     {         cout<<"a["<<i<<","<<j<<"] = ";         cin>>a[i][j];     }     cout<<"enter matrix b:"<<endl;     for(j=0;j<n;j++)     {         cout<<"b[0,"<<j<<"] = ";         cin>>b[0][j];     }     cout<<"enter accuracy = ";     cin>>e;     (i=0;i<n;i++)         t[i][0]=0;     while (l!=n)     {         l=0;         (i=0;i<n;i++)         {             x[i][0]=(1/a[i][i])*(b[i][0]);             (j=0;j<n;j++)             {                 if (j!=i)                 x[i][0]=x[i][0]-(1/a[i][i])*(a[i][j]*t[j][0]);             }         }         for(i=0;i<n;i++)         {             k=fabs(x[i][0]-t[i][0]);             if (k<=e)             {                 l=l+1;             }         }     (i=0;i<n;i++)         t[i][0]=x[i][0];     }     (i=0;i<n;i++)         cout<<"x"<<i+1<<"="<<x[i][0]<<endl;     getch();     return 0; } 

for example: (e.g.)

     // initializing variables n=2 e=0.001 a[0,0]=4 a[0,1]=2 a[1,0]=1 a[1,1]=3 b[0,0]=1 b[1,0]=-1  

the answer should x1=0.5 , x2=-0.5. output of code x1=0.35 , x2=-0.45.

what's problem?

regards

your arrays they're short 1 row , 1 column. ask user n equations, allocate n-1 rows , columns a, b, x, t. declarations matricies , vectors should double a[n][n], etc. you're writing outside bounds of arrays , possibly overwriting data in matrix.

by way, got right answer (0.5, -0.5) when applied fix.