Java Loops

Loops repeat a block of code while a condition is true.

Loop	Use when	Checks condition
for	Number of iterations is known	Before each iteration
while	Iterations are not known in advance	Before each iteration
do-while	Body must run at least once	After each iteration

for Loop

Java

for (int i = 1; i <= 5; i++) {
    System.out.println("5 x " + i + " = " + (5 * i));
}

5 x 1 = 5 5 x 2 = 10 5 x 3 = 15 5 x 4 = 20 5 x 5 = 25

Java

int num = 1234, sum = 0;
while (num > 0) {
    sum += num % 10;
    num /= 10;
}
System.out.println("Sum of digits: " + sum);

Sum of digits: 10

Java

int i = 10;
do {
    System.out.println("i = " + i);
    i++;
} while (i < 5);   // body still ran once

i = 10

Java

String[] langs = {"Java", "Python", "C"};
for (String s : langs) {
    System.out.print(s + " ");
}

Java Python C

Which loop always executes its body at least once?

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