c++ - how can i print two matrices when i call them as two different input file? -

i tried print 2 matrices, matrix , b. when call 1 text file matrix a, program ok. when call text file of matrix b, program failed, leaving box saying "unhandled exception @ 0x00168a07 in newqr.exe: 0xc00000fd: stack overflow."

is wrong call 2 text file this? below code. generating algorithm qr householder method. since failed here, cant continue algorithm. hope know wrong here. here are:

test1.in matrix a:

1.00            -6.00            34.00           -1644.00             803.00          -42258.00            15524.00        -831864.00           285061.00       -15355806.00        5153062.00      -278046852.00 

test2.in matrix b:

-1875.00      17976.00        485714.00        -501810.00     5370.00       409584.00      -973084.00        559740.00  291495.00     9193128.00     -64643018.00      55199850.00     6351060.00    175638624.00   -1430791544.00    1249618200.00     120491745.00  3213894936.00  -27252104806.00   23932788870.00      2200175790.00 58033455312.00 -498213904852.00  438253167540.00  

this code:

#include <iostream> #include <fstream> #include <iomanip> #include <cmath>  #define m 6 #define n 2 #define x 6 #define y 4 #define max 100  using namespace std;  int main() {     double a[max][max], b[max][max];     int i, j;     ifstream ifp;     ifp.open("test1.in", ios::in);     cout << "matrix a" << setw(40) << endl;     for(i=0;i<m;i++)     {         for(j=0;j<n;j++)         {             ifp >> a[i][j];             cout << setw(20) << a[i][j];         }            cout << endl;     }     ifp.close();     ifp.open("test2.in", ios::in);     cout << "matrix b" << setw(40) << endl;     for(i=0;i<x;i++)     {         for(j=0;j<y;j++)        {           ifp >> b[i][j];           cout << setw(20) << b[i][j];        }         cout << endl;     }     ifp.close();     cin.get(); } 

i suspect problem current design of program : exception raised stack overflow exception means stack full.

this happens because both declared matrix , b on stack , reserving them huge space don't need (only maybe).

so think haev 2 possibilities : either decrease space allocated matrix, eg. decalring , b :

double a[m][n], b[m][n]; 

or can declare a , b on heap. so, suggest change type of matrix double[][]to std::vector< std::vector<double> > because vectors automatically store values on heap , won't have manually use newand delete.

#include <vector> int main() {     std::vector< std::vector<double> > a, b; // modified line !!     int i, j;     ifstream ifp;     ifp.open("test1.in", ios::in);     cout << "matrix a" << setw(40) << endl;     for(i=0;i<m;i++)     {         for(j=0;j<n;j++)         {             ifp >> a[i][j];             cout << setw(20) << a[i][j];         }            cout << endl;     }     ifp.close();     ifp.open("test2.in", ios::in);     cout << "matrix b" << setw(40) << endl;     for(i=0;i<x;i++)     {         for(j=0;j<y;j++)        {           ifp >> b[i][j];           cout << setw(20) << b[i][j];        }         cout << endl;     }     ifp.close();     cin.get(); } 

this little modification should enough :) !