The while loop

A for loop knows in advance which items it will go through. When you don't know how many times you'll repeat, like "until the savings reach the goal" or "until the connection succeeds", use while: it repeats as long as its condition is true, checking it before every iteration.

You'll often pair it with a variable that starts at zero and grows with every iteration, like saved += deposit, plus a counter alongside it that counts the iterations, like months += 1.

The loop only ends if something inside it eventually makes its condition false. If you forgot saved += deposit, saved < goal would stay true forever and the program would never stop. So before you write any while, ask yourself: which line is going to end it?