Programming Forums > Application Development > C

raghuveerd · Jun 19th, 2007, 12:32 AM

Hi
I am a beginer to C Programming.I was trying to open a .txt file for reading but couldnt do that this is my code..Help me out.

(Toggle Plain Text)

#include<stdio.h>
#include<conio.h>
main()
{
FILE *fp;
clrscr();
fp=fopen("raghu.txt","r");
if(fp==NULL)
printf("ERROR IN OPENING THE FILE");
else
{
printf("hi");
fprintf(fp,"\n HI");
}

fclose(fp);
getch();
}

niteice · Jun 19th, 2007, 1:23 AM

What do you mean "couldnt do that"? Your code looks like it should work.

Fall Back Son · Jun 19th, 2007, 2:01 AM

This won't fix whatever problem you are having, but make that

int main ()

and

return 0 ; at the end. DaWei said that on here once, so do it! Lol.

this might fix your problem:

Your code looks like it should work to me. You might consider that you won't be able to open a file for reading if that file doesn't exist. I'm not sure if that is the case (it might create a blank file called raghu.txt), but in any case, you shouldn't try to read from a file that doesn't exist. So look in your directory and make sure that there is a file in that directory called raghu.txt .

Also, you made a call to fprintf, and sent the output to "fp". However, fp was used for reading, not for writing. You are trying to write to a file that is open for reading. This will yield unexpected results, I would imagine. If you want to open for reading and writing, use r+ instead.

pegasus001 · Jun 19th, 2007, 6:03 AM

Post any errors that your compiler shows, if there is any. Maybe the conio.h doesn`t support the clrscr() function.

cheap freelancer · Jun 20th, 2007, 5:33 AM

open the file in write mode.

DaWei · Jun 20th, 2007, 6:01 AM

cheap freelancer, please review the forum's rules regarding commercial signatures.

java_roshan · Jun 25th, 2007, 5:57 AM

Quote:

Originally Posted by pegasus001

Maybe the conio.h doesn`t support the clrscr() function.

conio.h supports clrscr(); within Turbo C++ 3.0

@OP: please post any errors that you encounter while compiling, as mentioned earlier.

pegasus001 · Jun 25th, 2007, 11:46 AM

Quote:

Originally Posted by java_roshan

conio.h supports clrscr(); within Turbo C++ 3.0

By the way how do you know what compiler is the OP using????

lectricpharaoh · Jun 25th, 2007, 6:24 PM

You need to decide if you're trying to read from a file, write to a file, or both. As it stands, you're opening the file in read mode:

(Toggle Plain Text)

fp=fopen("raghu.txt","r");

You then try using an output function on this file:

(Toggle Plain Text)

fprintf(fp,"\n HI");

You want to either change the fopen() to use write mode (or read/write), or change the fprintf() to an input function, like fgets() or fscanf() (depending on your needs).

You might want to check this reference if you don't have documentation for the C standard library. It doesn't have everything, but it's got the essential stuff for C and C++.

Jun 19th, 2007, 12:32 AM	#1
raghuveerd Newbie Join Date: Jun 2007 Posts: 1 Rep Power: 0	Problem with opening a file Hi I am a beginer to C Programming.I was trying to open a .txt file for reading but couldnt do that this is my code..Help me out. (Toggle Plain Text) #include<stdio.h> #include<conio.h> main() { FILE fp; clrscr(); fp=fopen("raghu.txt","r"); if(fp==NULL) printf("ERROR IN OPENING THE FILE"); else { printf("hi"); fprintf(fp,"\n HI"); } fclose(fp); getch(); } #include<stdio.h> #include<conio.h> main() { FILE fp; clrscr(); fp=fopen("raghu.txt","r"); if(fp==NULL) printf("ERROR IN OPENING THE FILE"); else { printf("hi"); fprintf(fp,"\n HI"); } fclose(fp); getch(); }

Jun 19th, 2007, 2:01 AM	#3
Fall Back Son Professional Programmer Join Date: Oct 2006 Posts: 262 Rep Power: 2	This won't fix whatever problem you are having, but make that int main () and return 0 ; at the end. DaWei said that on here once, so do it! Lol. this might fix your problem: Your code looks like it should work to me. You might consider that you won't be able to open a file for reading if that file doesn't exist. I'm not sure if that is the case (it might create a blank file called raghu.txt), but in any case, you shouldn't try to read from a file that doesn't exist. So look in your directory and make sure that there is a file in that directory called raghu.txt . Also, you made a call to fprintf, and sent the output to "fp". However, fp was used for reading, not for writing. You are trying to write to a file that is open for reading. This will yield unexpected results, I would imagine. If you want to open for reading and writing, use r+ instead. Last edited by Fall Back Son; Jun 19th, 2007 at 2:13 AM.

Jun 19th, 2007, 6:03 AM	#4
pegasus001 Hobbyist Programmer Join Date: Nov 2006 Location: 163H Posts: 213 Rep Power: 2	Post any errors that your compiler shows, if there is any. Maybe the conio.h doesn`t support the clrscr() function. __________________ You never test the depth of a river with both feet. The believer is happy. The doubter is wise. Free speech carries with it some freedom to listen. The next generation will always surpass the previous one. It`s one of the never ending cycles of life.

Jun 20th, 2007, 5:33 AM	#5
cheap freelancer Newbie Join Date: Jun 2007 Location: askexpert.info Posts: 4 Rep Power: 0	open the file in write mode. __________________ Programming Tutorials \|Interview Question And Answer Freelance Web Designer\|Freelance Programmer

Jun 20th, 2007, 6:01 AM	#6
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	cheap freelancer, please review the forum's rules regarding commercial signatures. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Jun 19th, 2007, 1:23 AM	#2
niteice Programmer Join Date: Aug 2005 Posts: 98 Rep Power: 4	What do you mean "couldnt do that"? Your code looks like it should work.

Jun 25th, 2007, 6:24 PM	#9
lectricpharaoh Caffeinated Neural Net Join Date: Jun 2005 Location: Dry west coast of Canada Posts: 1,034 Rep Power: 5	You need to decide if you're trying to read from a file, write to a file, or both. As it stands, you're opening the file in read mode: (Toggle Plain Text) fp=fopen("raghu.txt","r"); fp=fopen("raghu.txt","r"); You then try using an output function on this file: (Toggle Plain Text) fprintf(fp,"\n HI"); fprintf(fp,"\n HI"); You want to either change the fopen() to use write mode (or read/write), or change the fprintf() to an input function, like fgets() or fscanf() (depending on your needs). You might want to check this reference if you don't have documentation for the C standard library. It doesn't have everything, but it's got the essential stuff for C and C++. __________________ And once again, Probability proves itself willing to sneak into a back alley and service Drama as would a copper-piece harlot. - Vaarsuvius, Order of the Stick

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Problem with opening a file