Segmentation Fault

kurtruk · Feb 21, 2014

Let me post the code first of all.

main.cpp:

Rich (BB code):

#include <iostream>
#include "Font.h"
#include "DisplayFunctions.h"
using namespace std;

DisplayFunctions dfObj;

int main()
{
    dfObj.getMsg();
    dfObj.createByteMap();
    return 0;
}

Font.h:

Rich (BB code):

#ifndef FONT_H
#define FONT_H

class Font
{
    public:
       /*Set Up font to ASCII character*/
      short int ASCII [127][8] = {
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     0
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     1
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     2
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     3
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     4
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     5
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     6
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     7
            {  0,   0,   0,   0,   0,   0,   0,   0},          //     8
            {  0, 256, 256, 256, 256, 256, 256, 256},          //     9
            { 60,  66, 169, 133, 133, 169,  66,  60},          //  ☺  10
            {  0,   8,   8,   8,  42,  28,   8, 256},          //  →  11
            {  0,   8,  28,  42,   8,   8,   8, 256},          //  ←  12
            {  0,  16,  32, 127,  32,  16, 256, 256},          //  ↑  13
            {  0,   4,   2, 127,   2,   4, 256, 256},          //  ↓  14
            {  0,   4,   2,  49,   1,  49,   2,   4},          //  (: 15
            {  0,  17,  41,  41,  69,  69, 256, 256},          //  ≤  16
            {  0,  69,  69,  41,  41,  17, 256, 256},          //  ≥  17
            {  0,  29,  39,  32,  39,  29, 256, 256},          //  Ω  18
            {  0,  63,   2,   2,   4,  62, 256, 256},          //  µ  19
            {  0,  21,  22,  28,  52,  84, 256, 256},          //  ≠  20
            {  0,  16,  15,  24,   8,  31,   8, 256},          //  π  21
            {  0,  18,  36,  36,  18,  36, 256, 256},          //  ≈  22
            {  0,   6,   1,   6,  56, 192, 256, 256},          //  √  23
            {  0,   8,   8,  42,   8,   8, 256, 256},          //  ÷  24
            {  0, 249,   0, 249, 256, 256, 256, 256},          //  ‼  25
            {  0,  24,  36,  36,  24,  36, 256, 256},          //  α  26
            {  0,   3,   7, 254,  64,  48, 256, 256},          //  ♪  27
            {  0,   3,  31,  32,  64, 140, 252, 256},          //  ♫  28
            {  0,   6,   1,   6, 248, 128, 128, 256},          //  √  29
            {  0, 255, 255, 255, 255, 255, 256, 256},          //  █  30
            {  0,  34,  34, 250,  34,  34, 256, 256},          //  ±  31
            {  0,   0,   0,   0,   0, 256, 256, 256},          //     32
            {  0, 249, 256, 256, 256, 256, 256, 256},          //  !  33
            {  0, 224,   0, 224,   0, 256, 256, 256},          //  "  34
            {  0,  20, 127,  20, 127,  20, 256, 256},          //  #  35
            {  0,  38,  82, 255,  74,  36, 256, 256},          //  $  36
            {  0, 193, 198,  24,  99, 131, 256, 256},          //  %  37
            {  0,  54,  73,  85,  34,   5, 256, 256},          //  &  38
            {  0, 224,   0, 256, 256, 256, 256, 256},          //  '  39
            {  0,  60,  66, 129, 256, 256, 256, 256},          //  (  40
            {  0, 129,  66,  60, 256, 256, 256, 256},          //  )  41
            {  0,  80,  32, 248,  32,  80, 256, 256},          //  *  42
            {  0,   8,   8,  62,   8,   8, 256, 256},          //  +  43
            {  0,   1,   6, 256, 256, 256, 256, 256},          //  ,  44
            {  0,   8,   8,   8,   8,   8, 256, 256},          //  -  45
            {  0,   3,   3, 256, 256, 256, 256, 256},          //  .  46
            {  0,   1,   6,  24,  96, 128, 256, 256},          //  /  47
            {  0, 126, 129, 129, 129, 126, 256, 256},          //  0  48
            {  0,  33,  65, 255,   1,   1, 256, 256},          //  1  49
            {  0,  97, 131, 133, 137, 145,  97, 256},          //  2  50
            {  0, 129, 137, 137, 137, 118, 256, 256},          //  3  51
            {  0, 248,   8,   8,   8, 255, 256, 256},          //  4  52
            {  0, 226, 145, 145, 145, 146, 256, 256},          //  5  53
            {  0,  62,  81, 145, 145,  14, 256, 256},          //  6  54
            {  0, 129, 134, 152, 160, 192, 256, 256},          //  7  55
            {  0, 118, 137, 137, 137, 118, 256, 256},          //  8  56
            {  0, 112, 137, 137, 138, 124, 256, 256},          //  9  57
            {  0,  54,  54, 256, 256, 256, 256, 256},          //  :  58
            {  0,  49,  54, 256, 256, 256, 256, 256},          //  ;  59
            {  0,   8,  20,  20,  34,  34, 256, 256},          //  <  60
            {  0,  20,  20,  20,  20, 256, 256, 256},          //  =  61
            {  0,  34,  34,  20,  20,   8, 256, 256},          //  >  62
            {  0,  64, 128, 133, 136, 112, 256, 256},          //  ?  63
            {  0,  60,  66, 153, 165, 189, 133, 121},          //  @  64
            {  0,  63,  72, 136,  72,  63, 256, 256},          //  A  65
            {  0, 255, 137, 137, 137, 118, 256, 256},          //  B  66
            {  0, 126, 129, 129, 129,  66, 256, 256},          //  C  67
            {  0, 255, 129, 129,  66,  60, 256, 256},          //  D  68
            {  0, 255, 137, 137, 137, 129, 256, 256},          //  E  69
            {  0, 255, 136, 136, 136, 128, 256, 256},          //  F  70
            {  0, 126, 129, 129, 137,  78, 256, 256},          //  G  71
            {  0, 255,   8,   8,   8, 255, 256, 256},          //  H  72
            {  0, 129, 129, 255, 129, 129, 256, 256},          //  I  73
            {  0,   6,   1,   1, 129, 254, 256, 256},          //  J  74
            {  0, 255,   8,  52,  66, 129, 256, 256},          //  K  75
            {  0, 255,   1,   1,   1,   1, 256, 256},          //  L  76
            {  0, 255,  64,  32,  16,  32,  64, 255},          //  M  77
            {  0, 255,  64,  48,  12,   2, 255, 256},          //  N  78
            {  0, 126, 129, 129, 129, 129, 126, 256},          //  O  79
            {  0, 255, 136, 136, 136, 112, 256, 256},          //  P  80
            {  0, 126, 129, 129, 133, 130, 125, 256},          //  Q  81
            {  0, 255, 136, 140, 138, 113, 256, 256},          //  R  82
            {  0, 114, 137, 137, 137,  79, 256, 256},          //  S  83
            {  0, 128, 128, 255, 128, 128, 256, 256},          //  T  84
            {  0, 254,   1,   1,   1,   1, 254, 256},          //  U  85
            {  0, 248,   6,   1,   6, 248, 256, 256},          //  V  86
            {  0, 254,   1,   3,  28,   3,   1, 254},          //  W  87
            {  0, 195,  36,  24,  24,  36, 195, 256},          //  X  88
            {  0, 240,   8,   7,   8, 240, 256, 256},          //  Y  89
            {  0, 131, 133, 137, 145, 161, 193, 256},          //  Z  90
            {  0, 255, 129, 129, 256, 256, 256, 256},          //  [  91
            {  0, 128,  96,  24,   6,   1, 256, 256},          //  \  92
            {  0, 129, 129, 255, 256, 256, 256, 256},          //  ]  93
            {  0,  32,  64, 128,  64,  32, 256, 256},          //  ^  94
            {  0,   1,   1,   1,   1,   1, 256, 256},          //  _  95
            {  0, 128,  64,  32, 256, 256, 256, 256},          //  `  96
            {  0,   2,  21,  21,  21,  15, 256, 256},          //  a  97
            {  0, 255,  17,  17,  17,  14, 256, 256},          //  b  98
            {  0,  14,  17,  17,  17, 256, 256, 256},          //  c  99
            {  0,  14,  17,  17,  17, 255, 256, 256},          //  d  100
            {  0,  14,  21,  21,  21,  12, 256, 256},          //  e  101
            {  0,   8, 127, 136, 128,  64, 256, 256},          //  f  102
            {  0,  24,  37,  37,  37,  62, 256, 256},          //  g  103
            {  0, 255,   8,  16,  16,  15, 256, 256},          //  h  104
            {  0,  95, 256, 256, 256, 256, 256, 256},          //  i  105
            {  0,   2,   1,   1,  94, 256, 256, 256},          //  j  106
            {  0, 255,   8,  20,  34,   1, 256, 256},          //  k  107
            {  0, 129, 255,   1, 256, 256, 256, 256},          //  l  108
            {  0,  31,  16,  12,  16,  15, 256, 256},          //  m  109
            {  0,  31,   8,  16,  16,  15, 256, 256},          //  n  110
            {  0,  14,  17,  17,  17,  14, 256, 256},          //  o  111
            {  0,  31,  20,  20,  20,   8, 256, 256},          //  p  112
            {  0,   8,  20,  20,  12,  31, 256, 256},          //  q  113
            {  0,  31,   8,  16,  16,   8, 256, 256},          //  r  114
            {  0,   9,  21,  21,  21,  18, 256, 256},          //  s  115
            {  0,  16, 254,  17,   2, 256, 256, 256},          //  t  116
            {  0,  31,   1,   1,   2,  31, 256, 256},          //  u  117
            {  0,  28,   2,   1,   2,  28, 256, 256},          //  v  118
            {  0,  30,   1,   6,   1,  30, 256, 256},          //  w  119
            {  0,  17,  10,   4,  10,  17, 256, 256},          //  x  120
            {  0,  24,   5,   5,   5,  30, 256, 256},          //  y  121
            {  0,  19,  21,  21,  25, 256, 256, 256},          //  z  122
            {  0,  24, 126, 129, 256, 256, 256, 256},          //  {  123
            {  0, 255, 256, 256, 256, 256, 256, 256},          //  |  124
            {  0, 129, 126,  24, 256, 256, 256, 256},          //  } 125
            {  0,   8,  16,  16,   8,  16, 256, 256},          //  ~  126
        };
};

#endif // FONT_H

kurtruk · Feb 21, 2014

DisplayFunctions.h

Rich (BB code):

#ifndef DISPLAYFUNCTIONS_H
#define DISPLAYFUNCTIONS_H

class DisplayFunctions
{
    public:
        short int *rmsgByteMap;
        char msg [512];
        int numberOfCol;
        int characterArrayLength[];

        void getMsg();
        char createCharacterByteMap(char c);
        void createByteMap();
        void send();
};
#endif // DISPLAYFUNCTIONS_H

DisplayFunctions.cpp:

Rich (BB code):

#include "DisplayFunctions.h"
#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
#include<stdio.h>
#include<conio.h>
#include "Font.h"
using namespace std;

Font fontObj;

void DisplayFunctions::getMsg(){
    int characterLength =0;
    int msgLength=0;
    cin.getline(msg, 512);

    for(msgLength = 0; msg[msgLength] != '\0'; msgLength++);

    for(int character = 0; character < msgLength; character++){
        for(int i=0; i < 8; i++){
            if (fontObj.ASCII[(msg[character])] != 256){
                characterLength++;
            }
        }
        characterArrayLength[character] = characterLength;
        numberOfCol += characterLength;
        characterLength = 0;
    }
}

void DisplayFunctions::createByteMap(){
    rmsgByteMap=new short int[numberOfCol];
    int Character = 0;
    int charColIndex=0;

    for (int col=0;col<numberOfCol;col++){
        rmsgByteMap[col] = fontObj.ASCII[msg[Character]][charColIndex];
        charColIndex++;

        if(charColIndex == characterArrayLength[Character]){
            charColIndex = 0;
            Character++;
        }
    }
    cout << "rmsgByteMap = " << endl;
    cout << "{";
    for(int col=0;col<numberOfCol;col++){
        cout << rmsgByteMap[col] << ", ";
    }
    cout << "}" << endl;
}

I get a segmentation fault.

Stepping though the program reveals that it happens at the very end even after return 0;

I am unfamiliar with debugers. The "call stack" says 00457CDA std::basic_ostream<wchar_t, std::char_traits<wchar_t> >::flush()

Here's some more info that I scarcely know the meaning of:
Problem Event Name: APPCRASH
Application Name: MATRIX~1.EXE
Application Version: 0.0.0.0
Application Timestamp: 5307fff6
Fault Module Name: MATRIX~1.EXE
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 5307fff6
Exception Code: c0000005
Exception Offset: 00057cda
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 1033
Additional Information 1: fdef
Additional Information 2: fdef00b82efcfeb2a8d9fda4b24bbd53
Additional Information 3: 965d
Additional Information 4: 965df9fcde076979e37092106956450b

It only happens when the message that the user enters is somewhat long.
So why am I getting a segmentation fault?

spinnaker · Feb 21, 2014

Google is an amazing thing

https://www.google.com/search?q=seg...la:en-US:official&client=firefox-a&channel=sb

kurtruk · Feb 22, 2014

I have googled segmentation fault and could note find where my code went wrong.

spinnaker · Feb 22, 2014

1. You now know what causes that error now (in general).

2. You have the code.

3. You should have a debugger.

You have everything you need. Just step through the code and watch where your code is going out of bounds accessing memory.

More than likely it is characterArrayLength. You need to allocate memory. You can't do it like this characterArrayLength[];. That is an array with no memory allocated.

If you want to be a programmer then you need to become familiar with debuggers.

kurtruk · Feb 22, 2014

More than likely it is characterArrayLength. You need to allocate memory. You can't do it like this characterArrayLength[];. That is an array with no memory allocated.

Thanks SO MUCH, that worked.

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Segmentation Fault

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