[Vince]

The ampersand (&) means that a variable is passed "by reference" which means the function can alter the original variable. Unlike variables that are passed "by value" (the default) where - in a sense - a copy of the original variable is sent instead. For example:

PHP Code:

main()
{
    new byref;
    printf("%d", byref); // prints 0
    DoSomethingWithByRef(byref);
    printf("%d", byref); // prints 5
}

DoSomethingWithByRef(&value)
{
     value = 5;
} 


In the case of strtok, the idx (index) variable stores the position where a space was encountered. So if strtok is called again with the same idx parameter (which now does have a value) it will start its search from that position onward. However, strtok is horribly outdated. Don't use it. Use sscanf instead.