Programming basics

Loops

There are several more complicated structures called loops.

In case of if condition - statement executes only once if satisfied. Conditions inside loops are executed several times.

First example is FOR loop.

snowBall = 0;

for(a=1; i<11; i++) {
	snowBall += a;
}

In this example loop will repeat 10 times – the for statement will count variable a from 1 to 10 every time incrementing it. So snowBall values will be 1 , 3 , 6, 10 and so on.

While loop will repeat as many times as necessary to satisfy the predefined condition.

snowBall = 1; 

while(snowBall < 100) {
		snowBall = snowBall*2;
	}

snowBall variable will increase every loop - 1, 2, 4, 8, 16, 32, 64 …. And 128. After that condition is satisfied and it's impossible to enter loop any more. If we change a while condition to 1000, loop will make three more turns - 256, 512 and 1024.

Do loop is very similar – the only difference that even if the condition is not satisfied from the very beginning loop still will execute once.

snowBall= 1024;

do {
	snowBall = snowBall * 2;
} while (snowBall <100)

As a result variable snowBall will receive a value 1024

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