nullpointerexception - NullReferenceException was unhandled Object reference not set to an instance of an object. c# -

i tried running program, , have compared code friend's code, error keeps on showing though tried changing these lines (which think error coming from):

try {     filestream b = new filestream(@"c:\user\user_2\desktop\board.txt", filemode.open);     streamreader stream = new streamreader(b);      int x = 0;     while (!stream.endofstream)     {         if (x == 0)             g1 = stream.readline().split(' ');         else if (x == 1)             g2 = stream.readline().split(' ');         else if (x == 2)             g3 = stream.readline().split(' ');          x++;     }     stream.close();     b.close(); } catch (exception e) { } 

the program used check text file contains these 3 lines:

 o . x  x o . x . o 

...and see if there winner.

this part visual studio highlights error:

int n = 0; int m = n + 1; int o = m + 1;  boolean result = false; int winner = 0; string dw = "";  while (n <= 2) {     // in if-statement error:     if (g1[n].equals(g2[n]) && g2[n].equals(g3[n]) && !g1[n].equals("."))     {         result = true;         winner++;         dw = g1[n];     }     if (g1[n].equals(g1[m]) && g1[m].equals(g1[o]) && !g1[n].equals("."))     {         result = true;         winner++;         dw = g1[n];     }     else if (g2[n].equals(g2[m]) && g2[m].equals(g2[o]) && !g2[n].equals("."))     {         result = true;         winner++;         dw = g2[n];     }     else if (g3[n].equals(g3[m]) && g3[m].equals(g3[o]) && !g3[n].equals("."))     {         result = true;         winner++;         dw = g3[n];     }     else if (g1[n].equals(g2[m]) && g2[m].equals(g3[o]) && !g1[n].equals("."))     {         result = true;         winner++;         dw = g1[n];     }     else if (g3[n].equals(g2[m]) && g2[m].equals(g1[o]) && !g3[n].equals("."))     {         result = true;         winner++;         dw = g3[n];     }     n++; } 

i don't know know, can't make work.

edit: tried printing out values of arrays before if statements doesn't print out. sorry guys, i'm new here.

first of all, try reading file this:

using system.io;  try {     var file = @"c:\user\user_2\desktop\board.txt";     var lines = file.readalllines(file).tolist();     var g1 = lines[0].split(' ');     var g2 = lines[1].split(' ');     var g3 = lines[2].split(' '); } catch (exception e)  {      throw e;  } 

probably you'll exception thrown.

the line catch (exception e) { } culprit not being notified there exception. should handle exceptions catch in code.

p.s. have use c:\users\... in path, instead of c:\user\.... anyway, make sure use valid path file.