int d=(a>b)?a:b

This code defines a variable `d` that is assigned the value of either `a` or `b`, depending on which one is greater. This is achieved using the ternary operator `? :`, which is a shorthand way of writing an if-else statement.

The syntax of the ternary operator is as follows:

`condition ? value_if_true : value_if_false`

If the condition evaluates to true, the expression returns `value_if_true`, otherwise it returns `value_if_false`.

In this case, the condition is `(a>b)`, which checks whether `a` is greater than `b`. If it is true, `d` is assigned the value of `a`, otherwise it is assigned the value of `b`.