fstream

[ab1988]

when i run this code it gets compiled successfully but after running gives me an error and closes down abruptly!!!



#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include<cstdlib>
#include<iostream.h>
#include<fstream.h>
#include<string.h>

int main(void)
{
fstream file1,file2;
char *str=NULL,ch;
int i=0,j=0;
//clrscr();
free(str);
str = (char*) malloc(sizeof(char*));


i=0;
file1.open("c:/Dev-Cpp/ab/lan1.txt",ios::in) ;
file2.open("c:/Dev-Cpp/ab/lan11.txt",ios::out);
while(file1)
{
file1.get(ch);
str[i]=ch;
if(str[i]=='M' || str[i-1]=='A'&& str[i-1]=='P')
i=i-32;
i++;

}
for(j=0;j<i;j++)
file2<<str[j];
file1.close();
file2.close();
free(str);

}
getch();
return 0;
}

[kbw]

str = (char*) malloc(sizeof(char*)); allocates a block of four bytes (typically).

The while loop will a probably go around more than four times, causing you to overrun your four byte buffer, which corrupts the heap, which puts the program in an indetermate state.