Thread: Problem with segmentation fault

Hi everyone,

I have been having trouble writing a seemingly easy program. My program must remove all white space from a string without the use of string functions or an auxiliary string.

Here is my attempt to solve this,

Code:

void removewhitespace(char *str)
{
  int i=0,j=0;
  while(str[i] != '\0'){
    if(str[i] != (' '||'\n'||'\t')){ //both characters increment
      str[j]=str[i];
      i++;
      j++;}
    else{ //if character is white space, i increments and starts replacing the white space at j.
      i++;
    }
  }
}

I get a segmentation fault on line 6. I honestly can't figure out what is causing this problem. I would think that my while statement would stop the program from accessing memory beyond the bounds of the string.

Thanks for the help with that if statement. I still can't figure out why I am getting a segmentation fault though. I am debugging the program in gdb and str[i] and str[j] both print out as the first letter of my input string after I run the program once.
In case it helps, this is the program I am using to test my function,

Code:

void main(int argc, char **argv){
char *teststring = "I'm doing  great!\t\n";
removewhitespace(teststring);
printf("%s\n", teststring);
}

Thank you so much, that fixed my segmentation fault problem. Why is it that the string created by a pointer doesn't work the same as a string created as an array?