I have this:

Code:

void toggleString(const char *str, char *toggled)
{
	while ( *str != '\0') {
		if ( islower( *str ) ) /* if character is lowercase */
			*toggled = toupper ( *str ); /* convert to uppercase */
		else if ( isupper ( *str) )
			*toggled = tolower ( *str );
		++str; /* move str to the next character */
		++toggled;
	}
}

I want to change lower letters to upper and vice versa in a string. However, the code only work for first word and skip the rest. Could someone give me a hint?
Thanks.

You're not terminating the string at toggled.
If the character is not uppercase or lowercase, (like maybe a blank), you're not copying it, and thus advancing toggled pointer over an arbitrary (and possible null terminating) character.

Todd

When the current value of *str is not a letter, you don't copy it over to toggled. Hence whatever was already there stays (since you skip over it with ++toggled).

Then, is it possible to fix that I have so far?

Yes. In fact, both of us told you how to do so.

How do I check the current value is a space or not?

To answer your literal question: isspace. (Actually any whitespace, including tabs.) To answer the question you're actually asking: if it's not isupper and it's not islower, then it's some sort of something else, punctuation or whatever. So just copy it.

Wow, just like you said. It works now.
Thanks a lot.

Originally Posted by tabstop

To answer your literal question: isspace. (Actually any whitespace, including tabs.) To answer the question you're actually asking: if it's not isupper and it's not islower, then it's some sort of something else, punctuation or whatever. So just copy it.

Wow, just like you said. It works now.
Thanks a lot.