Member Avatar for Lun

is it possible to change the space into underline?

coz i don't know how to program that in C...

please help!!

  • 4 Contributors
  • 3 Replies
  • 113 Views
  • 22 Hours Discussion Span
  • Latest Post Latest Post by ~s.o.s~

Dani AI

Generated

Clarification and safe approach (short)

If by "underline" you mean the underscore character _, then yes — replace every space character ' ' with '_'. and were right in intent, and 's example demonstrates the basic idea. Two common pitfalls to avoid: do not modify a string literal (use a writable buffer), and avoid computing a loop limit as strlen(...) - 1 because that can skip the last character or underflow for an empty string.

A simple, robust pattern
Read into a writable buffer (for example with fgets), strip a trailing newline, then iterate from the first character up to the null terminator and replace spaces. Example:

#include <stdio.h>
#include <string.h>
#include <ctype.h>

int main(void)
{
    char s[256];
    if (!fgets(s, sizeof s, stdin)) return 1;
    s[strcspn(s, "\n")] = '\0';
    for (char *p = s; *p; ++p)
        if (*p == ' ') *p = '_';
    puts(s);
    return 0;
}

Notes, caution, and alternatives

  • If you want to replace any whitespace (tabs, vertical tabs, etc.) use isspace((unsigned char)*p), but remember to cast to unsigned char before calling ctype.h functions.
  • For Unicode (UTF-8) input a single char scan will not catch non-ASCII spaces (no-break space, etc.). Use a Unicode-aware library or wide-character APIs for those cases.
  • For performance on very large buffers, using strchr in a loop to find the next space can be slightly faster than checking every character, but the simple scan above is fine for most uses.

Common mistakes to check for: off-by-one loops, modifying read-only memory, leaving the input newline in place, and passing signed char values to ctype functions.

Recommended Answers

All 3 Replies

Member Avatar for Dave Sinkula

If a character is a string, change it to an underscore. Later, rinse, repeat (if necessary).

Post an attempt. Read the announcement in this forum if you need clarification of my last statement.

Member Avatar for dilip.mathews

"If a character is a string, change it to an underscore"
I guess Dave meant
"If a character is a space, change it to an underscore"

Member Avatar for ~s.o.s~

Maybe something along these lines should do the job in a simple way.

char* changeString (char* sourceStr)
{
    char* tmpStr = sourceStr;
    int strLength = strlen (tmpStr) - 1;
    for (int i =0; i < strLength; ++i) {
        if ( *(tmpStr + i) == ' ')
            *(tmpStr + i) = '_';
    }
    return tmpStr;
}

int main () {
    char name[BUFSIZ];
    fputs ("\nEnter the string: ");
    fgets (name, BUFSIZ, stdin);
    fputs ("\nThe new string is: ", stdout);
    fputs (changeString(name), stdout);
    getchar ();
    return 0;
}

Hope it helped,
Bye.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.