Operators
Arithmetic, assignment, comparison and logical operators in Java.
Operators combine values into new values. Java's operators will look familiar if you have seen C or JavaScript, but Java is stricter about types, which affects division and comparisons.
Arithmetic
public class Main {
public static void main(String[] args) {
int a = 17, b = 5;
System.out.println(a + b);
System.out.println(a - b);
System.out.println(a * b);
System.out.println(a / b); // int / int drops the remainder
System.out.println(a % b); // remainder
System.out.println(a / 5.0); // one double makes the result a double
System.out.println(Math.pow(2, 10));
}
}Output
22 12 85 3 2 3.4 1024.0
Math.pow always returns a double, which is why it prints 1024.0.
Assignment and increment
public class Main {
public static void main(String[] args) {
int points = 10;
points += 15;
points -= 5;
points *= 3;
points /= 4;
points++;
System.out.println(points);
int i = 3;
System.out.println(i++); // prints 3, then i becomes 4
System.out.println(++i); // i becomes 5, then prints 5
}
}Output
16 3 5
Comparison and logical operators
Comparisons produce a boolean. Combine them with && (and), || (or) and ! (not).
public class Main {
public static void main(String[] args) {
int marks = 72;
boolean submitted = true;
System.out.println(marks >= 40);
System.out.println(marks == 100);
System.out.println(marks >= 40 && submitted);
System.out.println(marks > 90 || !submitted);
}
}Output
true false true false
Integer overflow
Each numeric type has a limit. Going past it wraps around without any error, so pick long when values can get large.
public class Main {
public static void main(String[] args) {
int big = Integer.MAX_VALUE;
System.out.println(big);
System.out.println(big + 1);
long safe = big + 1L;
System.out.println(safe);
}
}Output
2147483647 -2147483648 2147483648