Parsing a string

[sigur47]

i am writing a tokenizer to parse a string. e.g"T T && F && !".Every character is separated by space.I have set up my tokeniser to return T,T,&,F,&,!.The problem that i have is that its returning a space at the last character which i do not know where it is coming from

}
void parseexpressionfromcommandline(char * unparsedexpression,char *parsedexpression){
     
    if(unparsedexpression==NULL )
        printf("does not point to any address");
    else {
        char value;  //this would hold my value 
        int pos=0;
        
       
        while(*unparsedexpression!='\0'){
          
            while(!isspace(*unparsedexpression)&& (*unparsedexpression)!='\0'){
             value=(*unparsedexpression++);
           
            }//inneer while loop
        
        unparsedexpression++;
        parsedexpression[pos++]=value;
      
        }//outer while loop
        
        printf("%s \n",parsedexpression);
        printf("%u",strlen( parsedexpression));
         
    }//outer while loop
    
    
}

[Salem]

> if(unparsedexpression==NULL )
You need to do this before doing anything else - like for example using strlen()

> parsedexpression[pos++]=value;
Chances are, your parsed expression is an uninitialise string.

You need to do
parsedexpression[pos]='\0';
before you try to print it, or use strlen() on it.

[sigur47]

> if(unparsedexpression==NULL )
You need to do this before doing anything else - like for example using strlen()

> parsedexpression[pos++]=value;
Chances are, your parsed expression is an uninitialise string.

You need to do
parsedexpression[pos]='\0';
before you try to print it, or use strlen() on it.

I am confused.Does the printing add extra space to the parsed string.

[grumpy]

Your code never terminates parsedexpression with a trailing '\0'. printf's %s format and strlen() are both looking for that terminator .... which may not be there at all.

Wouldn't it be easier to simply remove the spaces from unparsedexpression?

[Salem]

If you don't add a \0 (or pre-fill the parsed string with \0), then you'll print whatever garbage was there up to wherever a \0 happens to be present.

> while(!isspace(*unparsedexpression)&& (*unparsedexpression)!='\0')
But then again, this is skipping ALL non-whitespace chars and then storing a space.

Perhaps you should be storing chars INSIDE this loop?