Loops

In Java there are three different types of loops:

• while loops
• for loops
• do while loops

while Loop

The while loop continuously executes as long as a given condition is True. The syntax looks like this

while(condition){
    Execution block
}

Here's a concrete example:

int i = 0;
while(i < 5){
  System.out.println(i);
  i++;
}

Notice that we first set a counter variable, i, to keep track of how many times the loop has run. Each time it runs, we increment this variable by 1 (that's what i++ is doing). While i is less than 5, we continue to iterate, printing out the value of i every time.

for loop

Next, let's look at the for loop. Here's what the general syntax looks like:

for(initialization; condition; increment or decrement){
    Execution block
}

And here's a concrete example:

for(int i = 0; i < 5; i++){
    System.out.println(i);
}

do while Loop

Finally, here is the syntax for the do while loop:

do {
 Execution block
} while(condition);

And here's a concrete example:

int i = 0;
do {
  System.out.println(i);
  i++;
} while(i < 5);

The do while loop is very similar to the while loop. The key distinction is that the do while loop runs the loop once first before it checks the condition. This means that even if the condition is false right from the start, the code inside the loop will still get run once.