Question

Why does

switch ([document currentTool]) {     case DrawLine:         NSBezierPath * testPath = [[NSBezierPath alloc]init];         //...rest of code that uses testPath.... 

result in

error:syntax error before '*' token

for testPath?

Answer 1

You can’t instantiate an object inside a case statement unless you put it inside a new scope. This is because otherwise you could do something like this:

switch( ... ) {     case A:        MyClass obj( constructor stuff );        // more stuff        // fall through to next case     case B:        // what is the value of obj here? The constructor was never called     ... } 

If you want the object to last for the duration of the case, you can do this:

switch( ... ) {     case A: {        MyClass obj( constructor stuff );        // more stuff        // fall through to next case     }     case B:        // obj does not exist here     ... } 

This is the same in Objective C as well as C and C++.