Beginner: Having trouble getting an input from a .txt file into a string

This is a discussion on Beginner: Having trouble getting an input from a .txt file into a string within the C Programming forums, part of the General Programming Boards category; Hi, wondering if anyone out there can help me with this. I'm learning C and having a bit of trouble ...

  1. #1
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    Unhappy Beginner: Having trouble getting an input from a .txt file into a string

    Hi, wondering if anyone out there can help me with this.
    I'm learning C and having a bit of trouble getting to grips with taking inputs from external files.
    I made a .txt file, test.txt, which simly contains the word: working

    I'm now trying to make a program in C that will open the txt file, read the word "working" into a string and print it back to me on the screen.
    Here's the code I have so far:

    Code:
    /*	A program to test file input using C */
    
    #include "stdio.h"
    #include "string.h"
    
    int main(void)
    {
    	/* Open test.txt file for reading */
    
    	FILE *fp;
    	fp=fopen("c:\\test.txt", "r");
    	//fprintf(fp, "Testing...\n");
    
    	/* Declare a string */
    	
    	char string[20];
    
    	/* Input data from file into string */
    
    	fgets(string, 20, fp);
    
    	/* Print string */
    
    	printf("This program is: ");
    	printf( "String: %s", string);
    
    	/* Wait for user's key press, then close */
    
    	return 0;
    }
    The program has no trouble opening the file, but when I declare the string the errors begin... Anyone know where I'm going wrong here?
    If it helps, here are the errors I'm coming up with:
    Code:
    : error C2143: syntax error : missing ';' before 'type'
    : error C2065: 'string' : undeclared identifier
    : warning C4047: 'function' : 'char *' differs in levels of indirection from 'int '
    : warning C4024: 'fgets' : different types for formal and actual parameter 1
    Once I get the hang of this I was hoping to be able to read from a list in a txt file (e.g. a list of names) and put each name into a string. If anyone could point me in the right direction with that as well it would be great

  2. #2
    CSharpener vart's Avatar
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    move declarations before other code in the function. it is not a C++ where you can mix declarations and other statements
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  3. #3
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    ah, brilliant! Thanks for your help Vart!
    sorry, stupid mistake.
    There's one other thing you might be able to help me with:
    If I have a txt file with a list of names (each line having a persons first and last name seperated by a tab)
    e.g. John Smith
    Is there a way to stop the string when it reads the 'tab' rather than a NULL value that I think is supposed to stop it? And will the next string start reading the file where the last one left off?

    If anyone has any links to sites with good beginner info about file input using C it would be helpful, any information at all really. I've worked through the CProgramming.com tutorial but just have a few extra questions

  4. #4
    CSharpener vart's Avatar
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    read full line then use strtok or 2 other methods suggested by Dave_Shinkula splitting up names (strings)
    to split the line into tokens
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  5. #5
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    Had a go with strtok. It works great! Just what I needed
    Thanks again for all your help!!

  6. #6
    Registered User kryptkat's Avatar
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    Code:
    #include "stdio.h"
    #include "string.h"
    could be changed to
    Code:
    #include <stdio.h>
    #include <string.h>
    the <> tell the compiler to look in the include dir and the "" tell the compiler to look in the immediate dir

    http://www.cprogramming.com/tutorial/c/lesson1.html

  7. #7
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    ah, wasn't aware of that
    thanks for the advice!

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