以下c ++代码中是否存在内存泄漏？

Question

I am writing my program for my DataMining project. I get segmentation error on my code. I tried to debug using the gdb and created core dump using ulimit in ubuntu.

Below is the error I was able to backtrace in gdb.

Python Exception <class 'gdb.MemoryError'> Cannot access memory at address 0x7fff48c47738: #0  0x000000000040cdb0 in TokenReader::getToken (
this=<error reading variable: Cannot access memory at address 0x7fff48c47718>, 
this@entry=<error reading variable: Cannot access memory at address 0x7fff48c47738>, 
buf=<error reading variable: Cannot access memory at address 0x7fff48c47710>, 
buf@entry=<error reading variable: Cannot access memory at address 0x7fff48c47738>) at src/tokread.c++:26
Cannot access memory at address 0x7fff48c47738

My code:

/*********************************************************
 * Project: 2
 * File: tokread.h
 * Anil Pediredla, KUID 28056
 *********************************************************/

#ifndef _TOKREAD_H_
#define _TOKREAD_H_

#include <iostream>
using namespace std;

const short NEW_LINE = 0;
const short SPACE    = 1;
const short TOKEN    = 2;
const short COMMENT  = 3;

class TokenReader {
  public:

    TokenReader(istream &in);

    char* getToken(char* buf);

  private:
    istream &in;
    short state;
};



#endif //_TOKREAD_H_

/*********************************************************
 * Project: 2
 * File: tokread.h
 * Anil Pediredla, KUID 28056
 *********************************************************/

#include <sstream>
#include <cstdlib>

using namespace std;

#include "tokread.h"


/*********************************************************
 * Class: TokenReader
 *********************************************************/
TokenReader::TokenReader(istream &in):
  in(in), state(NEW_LINE) {
}


char* TokenReader::getToken(char* buf) {
  bool done = false;
  int tokLen = 0;
  while (!done && !in.eof()) {           //error here
    char ch = in.get();
    switch (state) {
      case NEW_LINE:
        if (ch == '!') state = COMMENT;
        else {
          in.unget();
          state = SPACE;
        }
      break;
      case SPACE: 
        if ((ch == 13) && (in.peek() == '\n')) in.get();
        if (ch == '\n') {
          state = NEW_LINE;
          break;
        }
        if ((ch != ' ') && (ch != '\t')) {
          in.unget();
          state = TOKEN;
        }
      break;
      case TOKEN:
        if ((ch == 13) && (in.peek() == '\n')) in.get();
        if (ch == '\n') {
          state = NEW_LINE;
          done = true;
          break;
        }
        if ((ch == ' ') || (ch == '\t')) {
          in.unget();
          state = SPACE;
          done = true;
          break;
        }
        buf[tokLen++] = ch;
      break;
      case COMMENT:
       if (ch == '\n'){
           state = NEW_LINE;
       }
      break;
    }
  }
  buf[tokLen] = '\0';
  return buf;
}

I am calling my classes through a main function which looks like

 int main(int argc, char* argv[]) { fstream input(inFileName, ios::in); if (!input) { cerr << "Could not open file " << inFileName << endl; exit(-1); /* calling my error class here. */ TokenReader reader(input); Table* table = new Table(reader, maxDistAttrVal); table->mlem2(intvFormat, output1, output2, output3); } 

}

Answer 1

if you are building it for Window, you would be able to use the build in data leak code they provided for Visual Studioes(I have not tested the code outside Visual Basics)

   //-----MICROSOFT ONLY----------
  #define _CRT_DEBUG_MAP_ALLOC
  #include <crtdbg.h> //C-runtime debug header 
 //must be placed before include's
 //------------------------------

 //Must be place at the top of your main method
 #if defined(_DEBUG)
int dbgFlags = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
dbgFlags |= _CRTDBG_CHECK_ALWAYS_DF; //check block intergerity on every memory
dbgFlags |= _CRTDBG_DELAY_FREE_MEM_DF; //dont remove blocks on delete
dbgFlags |= _CRTDBG_LEAK_CHECK_DF; //check for leaks at process termination
_CrtSetDbgFlag(dbgFlags);
#endif

This code will make sure of any memorey leaks are cleaned up and the blocks wont be removed.