Post-increment within a self-assignment

Question

I understand the differences between i++ and ++i, but I\'m not quite sure why I\'m getting the results below:

static void Main(string[] args)
{
    int c = 4         


        

Answer 1

According to the MSDN page on C# operators the assignment operator (=) has lower precedence than any primary operator, such as ++x or x++. That means that in the line

c = c++;

the right hand side is evaluated first. The expression c++ increments c to 43, then returns the original value 42 as a result, which is used for the assignment.

As the documentation you linked to states,

[The second form is a] postfix increment operation. The result of the operation is the value of the operand before it has been incremented.

In other words, your code is equivalent to

// Evaluate the right hand side:
int incrementResult = c;   // Store the original value, int incrementResult = 42
c = c + 1;                 // Increment c, i.e. c = 43

// Perform the assignment:
c = incrementResult;       // Assign c to the "result of the operation", i.e. c = 42

Compare this to the prefix form

c = ++c;

which would evaluate as

// Evaluate the right hand side:
c = c + 1;                 // Increment c, i.e. c = 43
int incrementResult = c;   // Store the new value, i.e. int incrementResult = 43

// Perform the assignment:
c = incrementResult;       // Assign c to the "result of the operation", i.e. c = 43