how to remove newline from a string

This is a discussion on how to remove newline from a string within the C Programming forums, part of the General Programming Boards category; hi people. i tried looking for a function that chops the newline off of a string but couldnt find one ...

  1. #1
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    how to remove newline from a string

    hi people.

    i tried looking for a function that chops the newline off of a string but couldnt find one so i went about writing my own function to do it.

    here is the code
    Code:
    /* removes the newline character from a string */
    char* chop(char *string)
    {
    	int i, len;
    	len = strlen(string);
    	char *newstring;
    
    	newstring = (char *)malloc(len-1);
    
    
    	for(i = 0; i < strlen(string)-1; i++)
    	{
    		newstring[i] = string[i]; 
    		printf("in the string %c\n", string[i]);
    	}
    
    	printf("len og newstring %d\n", strlen(newstring));
    	printf("string now .......... %s\n", newstring);
    
    	return newstring;
    }
    this doesnt seem to work because it keeps giving me a string which is longer than the len-1 size i require. it just seems to put garbage at the end of it.

    Any help is greatly appreciated

  2. #2
    ATH0 quzah's Avatar
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    If you insist on creating a new string...
    Code:
    char *choppy( char *s )
    {
        char *n = malloc( strlen( s ? s : "\n" ) );
        if( s )
            strcpy( n, s );
        n[strlen(n)-1]='\0';
        return n;
    }
    Eh, looks right. Not good mind you, much better ways to do this, but amusing and if correct, sufficient. :beer:


    Quzah.

    edit
    Last edited by quzah; 10-01-2005 at 05:00 AM.
    Hope is the first step on the road to disappointment.

  3. #3
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    how did the '\n' get in the string? fgets() normally (but not always) puts one there. All you have to do is replace the last character in the string with a 0, after verifying that the last character is a newline.
    Code:
    char str[80];
    int len;
    ...
    fgets(str,sizeof(str),fp);
    // remove newline
    len = strlen(str);
    if( str[len-1] == '\n' )
        str[len-1] = 0;
    Last edited by Ancient Dragon; 10-01-2005 at 05:33 AM.

  4. #4
    ---
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    Quote Originally Posted by Ancient Dragon
    fgets() normally (but not always) puts one there.
    When doesn't it? On a non standard implementaion?

    fgets

    Declaration:

    char *fgets(char *str, int n, FILE *stream);

    Reads a line from the specified stream and stores it into the string pointed to by str. It stops when either (n-1) characters are read, the newline character is read, or the end-of-file is reached, whichever comes first. The newline character is copied to the string. A null character is appended to the end of the string.

    On success a pointer to the string is returned. On error a null pointer is returned. If the end-of-file occurs before any characters have been read, the string remains unchanged.

  5. #5
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    possibly implementation defined -- this is from MSDN

    The fgets function reads a string from the input stream argument and stores it in string. fgets reads characters from the current stream position to and including the first newline character, to the end of the stream, or until the number of characters read is equal to n 1, whichever comes first. The result stored in string is appended with a null character. The newline character, if read, is included in the string.
    google "man fgets"
    The fgets() function reads at most one less than the number of characters specified by size from the given stream and stores them in the string str. Reading stops when a newline character is found, at end-of-file or error. The newline, if any, is retained. If any characters are read and there is no error, a `\0' character is appended to end the string.

  6. #6
    ... kermit's Avatar
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    If there is a newline and there is room for it in the destination, then it is copied over.

  7. #7
    Sys.os_type="Unix";;
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    You can do it lots of different ways..

    Code:
    if( (ptr = strchr(str, '\n')) != NULL)
        *ptr = '\0';

  8. #8
    Frequently Quite Prolix dwks's Avatar
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    I like to do this:
    Code:
    void chomp(char *s) {
        while(*s && *s != '\n' && *s != '\r') s++;
    
        *s = 0;
    }
    dwk

    Seek and ye shall find. quaere et invenies.

    "Simplicity does not precede complexity, but follows it." -- Alan Perlis
    "Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
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  9. #9
    ATH0 quzah's Avatar
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    Like I said, there are many ways to do it. Here's one I function-wrapped, origionally posted by Prelude:
    Code:
    void choppy( char *s )
    {
        s[strcspn ( s, "\n" )] = '\0';
    }

    Quzah.
    Hope is the first step on the road to disappointment.

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