For and Nested Loops

For loops

For loops are one of the most common types of loops and can be found in most programming languages. They take the following form:

for (initialization ; condition ; update) {
  // do something
}

Three things get set inside the parentheses:

• The initialization code is run before the loop starts and is usually employed to initialize any variables that are used in the loop.
• The condition has to be satisfied for the loop to continue.
• The update code is what to do after each iteration of the loop, and it is typically used to update any values.

This process is illustrated in the following diagram.