for… to and for… downto expressions

The for…to expression is used to iterate in a loop over a range of values of a loop variable. The for… downto expression reduces the value of loop variable.

for … in expression

This form of for loop is used to iterate over collections of items i.e., loops over collections and sequences

While…do loop

Repeats a statement or group of statements while a given condition is true. It tests the condition before executing the loop body.

nested loops

You can use one or more loop inside any other for or while loop.