// use of -- pre and post decrement unary operator

// subtract one from x and store it back in x, and then divide the decremented value of x by 2.
y = --x / 2;

// subtract one from x and store it back in x, and then divide the original undecremented value of x by 2.
y = x-- / 2;

// Avoid writing code that depends on exactly when x is decremented.
// You will baffle people trying to maintain your code, even if it works.
y = x-- + x;