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I get you completely but say if i make temp 50. There won't be any words past that capacity surely?
Also can i take whatever is in the else statement and put it outside with it still being in the while loop?
If i take it out of the while loop it will only ending up printing out the last word right??
Why not? No matter what size you give, I can always coin a word to be longer. (According to Wikipedia, the chemical name of the largest known protein is 189819 letters long, so you need an array of 189820 chars to store it as a string... and then I can just add a prefix or suffix and break your program as it is now.)Quote:
Originally Posted by killpoppop
What do you mean? The code in the else block is intended to be used to "finish up" the processing, so running it on each iteration does not make sense.Quote:
Originally Posted by killpoppop
hmm... this calls for a re-look of what you are trying to do. What is read() supposed to do? Why do you print in the read function, and why do you not return a value from the read() function despite giving it a non-void return type?Quote:
Originally Posted by killpoppop
Maybe your problem is not realloc at all. If you have an overflow somewhere else, these can sometimes show up and cause "a crash" after you have changed some completely unrelated piece of code, because it involves the location of data in memory.
That would make it a difficult problem to solve, and lead you to believe it's just the one change you made that did it.
However, you could at least try to use a debugger and find out why the segfault happens (if it is a segmentation fault, you still haven't explained what happens; keep in mind that there is a lot of reasons a program can suddenly stop running, usually accompanied by some kind of informative message. If you're just a user, say "crash", if you're the programmer, you better figure out what that really means).
I get what your saying although hopefully that wont be in the text document =] I just don't quite how i would implement your suggestion. So i would watch the value of i? Once it hits 30 double the size of the array?
To do with not giving a return value the function was void. The idea is i read in a text document, send it to the read function which takes a word at a time into the temp array. Eventually i want each word to be stored in a link list.
The reason for the print was a primary check to see if it was successfully taking out spaces and printing off the words. But i realised last night it needs a redesign =[ Ideally i would just send it up to the list in the read function. But it makes more sense to me to send it back to the main.
I'm currently running it on windows i'll hop over to gdb on ubuntu. All i get while running the program is a pop up that just says 'book.exe has stopped working' .Quote:
Originally Posted by MK27
You are already "watching" the value of i. You need to make the 30 into a variable, and use that variable to track the capacity (i.e., the size of the array, but not necessarily of the string).Quote:
Originally Posted by killpoppop
In that case the read() function might just read one word. It could have a return type of char*, and return NULL if there is an error or EOF is reached. You can then call read() and append the return value to a linked list.Quote:
Originally Posted by killpoppop
You should be able to use gdb on Windows as well. (I use gdb on Windows.)Quote:
Originally Posted by killpoppop
And as far as other code there isn't much else that could cause a problem.
To laserlight.
So you believe the problem with realloc is that there is a word bigger than 30 in the text document?
Or should i realloc is another location?
That might be the problem, or it might be merely a potential problem. Without the complete program and test input, it is difficult to say. (But no, do not post the entire program; post the smallest and simplest program that demonstrates the problem, and provide your test input.)Quote:
Originally Posted by killpoppop
Then just create any .txt file save in the same location and run.Code:#include <stdio.h>
#include<string.h>
#include <stdlib.h>
#include<ctype.h>
char read( FILE *text )
{
int i = 0 ;
char z, *temp ;
temp = calloc( 30, sizeof( char ) ) ;
/* Reads in the words one at a time to an array */
while( ( z = fgetc( text ) ) != EOF )
if( ( ( 65 <= z ) && ( z <= 90 ) ) || ( ( 97 <= z ) && ( z <= 122 ) ) || ( z == 45 ) || ( z == 39 ) )
{
temp[i] = z ;
temp[i] = toupper( temp[i] ) ;
i++ ;
}
else if( i != 0 && i < 30 )
{
temp[i]= '\0' ;
temp = realloc( temp, ( i+1 )*sizeof( char ) ) ;
i = 0 ;
printf( "%s %d\n", temp, strlen(temp) ) ;
}
}
int main( int argc, char *argv[] )
{
//list *n = NULL ;
FILE *text ;
if( argc != 2 )
{
printf( "Incorrect Syntax" ) ;
return 0 ;
}
else
text = fopen( argv[1], "r" ) ;
read( text ) ;
return 0 ;
}
eg.
book.exe "tester.txt"
Hope that is enough.
What was your test input?Quote:
Originally Posted by killpoppop
I suggest that you fix the buffer overflow bug that I pointed out. At the moment it is the most likely reason for the crash.
The Battle of Dien Bien Phu was the climactic battle of the First Indochina War between French Union forces and Viet Minh communist revolutionary forces. The battle occurred between March and May 1954, and culminated in a massive French defeat that effectively ended the war. The French undertook to create an air-supplied base at Dien Bien Phu, deep in the hills of Vietnam, in order to cut off Viet Minh supply lines into the neighboring French protectorate of Laos. The Viet Minh, under General Vo Nguyen Giap, surrounded and besieged the French, who were unaware of the Viet Minh's possession of heavy artillery. The Viet Minh occupied the highlands around Dien Bien Phu, and were able to fire down accurately onto French positions. Tenacious fighting on the ground ensued, reminiscent of the trench warfare of World War I. The French repeatedly repulsed Viet Minh assaults on their positions. Supplies and reinforcements were delivered by air, although as the French positions were overrun and the anti-aircraft fire took its toll, fewer and fewer of those supplies reached them. After a two month siege, the garrison was overrun and most French surrendered. Shortly after the battle, the war ended with the 1954 Geneva accords, under which France agreed to withdraw from its former Indochinese colonies.
Is in my test file.
EDIT:
A limited test input shows that the current problem might lie elsewhere, since you do reset i to 0 and no word is longer than 29 characters (at least at a glance). However, if you are going to limit each word to 29 characters, why use dynamic memory allocation? It just complicates the issue, plus you did not free the memory.
I compiled the code you posted and ran it on the text and I didn't have any problems. Have you checked on your other system yet?
Right can you explain this very briefly, i'm new to the language and understand it is an issue with memory. But as far as i can see no word is larger than 30 characters. But i'm obvious not on your wavelength =]