Stuck with C syntax

I am trying to remove spaces from the end of a char array (string).

This is the pseudo code of what I am doing, but it keeps deleting the whole str开发者_运维问答ing:

if(string length - 1 != a space)
    return

Otherwise, it must equal a space, so

while *mypointer-- != a space
//This should loop back to where there is a character.

Outside of the while loop, I now add one to the pointer by doing

mypointer ++;

and then set mypointer '\0' to signal the end of the string.

I am doing something fundamentally wrong inside of my while, but I cannot seem to figure it out. What could it be?

A little clairvoyance:

while(*mypointer == a space) {
    --mypointer;
}
mypointer[1] = '\0';

Notice that it is == a space not != a space.

#include <string.h>
...

char *mypointer = strrchr(string, ' ');
if (mypointer) *mypointer = '\0';

You're probably setting mypointer to \0, which sets the pointer to NULL. You need to set mypointer[1] to \0. Also, make sure you do the right thing for the following edge-cases:

• when a string is all spaces,
• when string length is 0.

Without the code we can just guess:

How is mypointer initialized?

Are you sure about the while loop condition? Should it be while 'last character is space'?

A slight improvement perhaps:

while(*mypointer == a space) {
  *mypointer-- = '\0';
}

Have a look at this code that does the exact job to strip spaces from the end of the string...this is from the Snippets archive - it's an educational thing to watch what's going on when stepping through the debugger and very useful collection of C code also...