C# Boolean expressions

Question

Hi, in the example below, what would 'foo' be set to each time? I've searched online but I can't find anywhere that gives me the answer:

static void Main(string[] args) {
   static public bool abc = true;
   static public bool foo = (abc = false);
   foo = (abc = true);
}

Answer 1

Use == instead of = for boolean expressions.

Answer 2

false the first time and true the second time. Remember that = is the assignment operator: it assigns the value of the second operand to the first, and then returns this value. For example:

int foo = 1;
int bar = (foo = 2);

The second line here assigns the 2 to foo, then returns 2 to the other assignment operator, which assigns 2 to bar. At the end of it all, both foo and bar have the value 2.

Edit: This is why it's valid to chain up assignment operations; e.g.

int foo;
int bar;
foo = bar = 2; // Equivalent to foo = (bar = 2);

Answer 3

Your static variable definitions should be placed at the class level, not inside a method. In that case the intializers will be run in the order they are defined in the source code.

This means that abc will first be set to true, then foo will be set to false since abc is true.

Answer 4

1. abc = true
2. abc = false. Then foo = false
3. abc = true. Then foo = true