1 - Conditional structure If & else else in Java
In Java, an if statement is a conditional statement that executes a set of statements according to a condition whether it is verified or not.
Syntax:
if( condition ){
set
of
statements
......
}
else{
set
of
statement...
...
}
Example
int youAge=19;
if(yourAge <= 18 ){
System.out.println("You are minor, because your age is : " + yourAge );
}
else{
System.out.println("You are major, because your age is : " + yourAge );
}
Here is a complete example
Example
import java.util.Scanner;
public class If {
public static void main(String[] args) {
System.out.println("How old are you !");
Scanner age=new Scanner(System.in);
int yourAge=age.nextInt();
if ( yourAge < 18 ) {
System.out.println("you are minor, because your age is : "+ yourAge);
}
else{
System.out.println("you are majorr, because your age is : "+ yourAge);
}
age.close();
}
}
This displays:
You are major, if the age typed is> = 18
You are minor, if the age typed is <18
Note :
The else { command is not required
2 - Loop For Java
There are many situations that require you to run a block of instructions several times in your applications. Loops can execute a block of code a number of times. The for Java loop will be useful in this case
Syntax:
For (start counter, end counter, counter increment) {
Block of instructions
}
Example:
For (int i = 1; i <= 10; i ++) {
System.out.println ("hello!");
}
The above example shows 10 times the message "Hello !"
Hello !
Hello !
Hello !
Hello !
Hello !
Hello !
Hello !
Hello !
Hello !
Hello !
3 - Java while loop
The while loop is a control statement that allows the code to be repeatedly executed as long as a boolean condition is achieved.
Syntax:
While (condition) {
Block of instructions ...
}
Example
Int i = 1;
While (i <= 10) {
System.out.println ("hello!");
i ++;
}
The above example shows 10 times the message hello! And stops.