What is expression that is executed by the for loop only once regardless of the number of iterations?

In a for loop, the expression that is executed only once, regardless of the number of iterations, is the initialization expression. This expression is typically found at the beginning of the loop's syntax and is used to initialize the loop variable. For example, in the loop for (int i = 0; i < n; i++), the initialization int i = 0 is executed just once before the loop begins iterating.