Simplest if statement
Java has two selection statements: if and switch.
Simplest if statement form is shown here:
if(condition)
statement;
condition is a boolean expression.
If
condition is true, then the statement is executed. If
condition is false, then the statement is bypassed. Here is an example:
public class Main {
public static void main(String args[]) {
int num = 99;
if (num < 100) {
System.out.println("num is less than 100");
}
}
}
The output generated by this program is shown here:
num is less than 100
Using if statement to compare two variables
public class Main {
public static void main(String args[]) {
int x, y;
x = 10;
y = 20;
if (x < y){
System.out.println("x is less than y");
}
x = x * 2;
if (x == y){
System.out.println("x now equal to y");
}
x = x * 2;
if (x > y){
System.out.println("x now greater than y");
}
if (x == y){
System.out.println("===");
}
}
}
The output generated by this program is shown here:
x is less than y
x now equal to y
x now greater than y
Using a boolean value to control the if statement
The value of a boolean variable is sufficient, by itself, to control the if statement.
public class Main {
public static void main(String args[]) {
boolean b;
b = false;
if (b) {
System.out.println("This is executed.");
} else {
System.out.println("This is NOT executed.");
}
}
}
There is no need to write an if statement like this:
if(b == true) ...
The output generated by this program is shown here:
This is NOT executed.