Remove '|' from a string

Question

I wrote the below code which replaces '|' characters from the string.

#include <stdio.h>
#include <stdlib.h>

void remove_pipes(char*);

main (int argc, char **argv)
{

char string1[] = "|||||||||||||";
remove_pipes(string1);
printf("String1 = %s", string1);
char string2[] = "h|e|l|l|o";
remove_pipes(string2);
printf("String2 = %s", string2);
}

void remove_pipes(char* input)
{
  for(; *input; input++)
  {
      if(*input == '|')
      {
          *input = ' ';
      }
  }
}

Now I need to modify this method to remove the '|' character from the string. I am not sure how to do that. Hope someone can give me some hint.

Wow!! so much for removing pipe from a string. Simple `sed 's/|//g'` would have done the trick for you. — jaypal singh, Dec 21 '11 at 08:07
Looks like some text editor should work for OP: both to prove possibility of the task and to actually perform the task :). — Alexei Levenkov, Dec 21 '11 at 08:08
@jlliagre - I am not asking for code solution here, the code above i did from scratch based on some of the previous posting in stack overflow. I am just asking a hint. Since this variable is a pointer, how do I remove a character, that is where I am stuck. Could I just initialize another variable and append the non '|' values and reassign the variable content to char* input? — Nanthini Muniapan, Dec 21 '11 at 08:09
@JaypalSingh - Right now I need this to be implemented in c program. This is a small chunk of a bigger program. This program will read content of xml file and check whether there are any '|' characters present and remove it. — Nanthini Muniapan, Dec 21 '11 at 08:11
Look at http://stackoverflow.com/questions/779875/what-is-the-function-to-replace-string-in-c. — Vadzim, Dec 21 '11 at 08:15
A hint: You can't just *delete* characters from a string. Given a string `"ab|cd"`, to change it to `"abcd"`, you need ``c`` in the position formerly occupied by ``|``, ``d`` in the position formerly occupied by `'c'`, and a terminating `'\0'` in the position formerly occupied by `'d'`. — Keith Thompson, Dec 21 '11 at 10:02

score 4 · Accepted Answer · answered Dec 21 '11 at 08:13

Use a char pointer to travel the input and modify it:

#include <stdio.h>
#include <stdlib.h>

void remove_pipes(char*);

main (int argc, char **argv)
{

    char string1[] = "|||||||||||||";
    printf("String1 = %s\n", string1);
    remove_pipes(string1);
    printf("String1 = %s\n", string1);
    char string2[] = "h|e|l|l|o";
    printf("String2 = %s\n", string2);
    remove_pipes(string2);
    printf("String2 = %s\n", string2);
}

void remove_pipes(char* input)
{
    unsigned idx = 0;
    char* aux = input;

    for(; *input; input++)
    {
        if (*input != '|')
        {
            *(aux + idx++) = *input;
        }
    }
    *(aux + idx) = '\0';
}

Thanks for the quick response and the answer. Clever way of manipulating pointers. Really appreciate it. — Nanthini Muniapan, Dec 21 '11 at 08:29

Remove '|' from a string

1 Answers1