control structures in java
// There are many control structures in Java including, if, if-else, swithc, while, for,
// and break. Here are related articles:
// https://docs.oracle.com/javase/tutorial/java/nutsandbolts/if.html
// https://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html
// https://docs.oracle.com/javase/tutorial/java/nutsandbolts/while.html
// https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html
// https://docs.oracle.com/javase/tutorial/java/nutsandbolts/branch.html