Lesson_2: Operations in Java

1. Capda toplama emeliyyatinin ferqi:

package org.example.test;

public class Test {
    public static void main(String[] args) throws Exception {
        int one = 1;
        int two = 2;
        System.out.println("result = " + one + two);
        System.out.println(one + two + " result");
    }

} 

char a = 'a';
char b = 'b';
System.out.println(a + b);
System.out.println('a' + 'b');
System.out.println("" + a + b);
System.out.println("" + 'a' + 'b');

2. float ve double-da bash veren riyazi emaliyyat xeyalari:

package org.example.test;

public class Test {
    public static void main(String[] args) throws Exception {
        float f = 0.6F;
        System.out.println(f + 0.1);
    }
}

Operators in Java

Operators in Java can be classified into 6 types:

1. Arithmetic Operators
2. Assignment Operators
3. Relational Operators
4. Logical Operators
5. Unary Operators
6. Bitwise Operators

1. Arithmetic Operators:

Addition +

Subtraction -

Multiplication *

Division /

Modulo %

int i = 5;
double d = 2.3;
double result = i + d;
System.out.println(result);
i += d;
System.out.println(i);

2. Assignment Operators:

=

+=

-=

*=

/=

%=

3. Relational Operators:

Relational Operators always return boolean value.

==

!=

>

<

>=

<=

4. Logical Operators:

Logical Operators always return boolean value.

Logical AND &&

Logical OR ||

Logical NOT !

5. Unary Operators

Unary plus + 

Unary minus -

Increment ++

Decrement --

Logical complement !

int i = -5;
int b = -i;
System.out.println(i);
System.out.println(b);

int a = 10;
++a;
a++;
System.out.println(a);

int a = 10;
System.out.println(a++);
System.out.println(++a);

Weird behaviour:

System.out.println("Normal behaviour");
int i = 0;
i = ++i;
System.out.println(i);
i = ++i + 2;
System.out.println(i);

System.out.println("Weird behaviour");
i = 0;
i = i++;
System.out.println(i);
i = i++ + 2;
System.out.println(i);

System.out.println("Normal behaviour too");
i = 0;
int j = i++;
System.out.println(i);
System.out.println(j);

6. Bitwise Operators

Bitwise complement ~

Bitwise AND &

Bitwise OR |

Bitwise XOR ^

Left shift <<

Right shift >>

Unsigned right shift >>>

package org.example;

public class Main {
    public static void main(String[] args) {
        if((getOne() == 1) && getTwo() == 2) {
            System.out.println("done");
        }
    }

    public static int getOne() {
        System.out.println("getOne is called");
        return 1;
    }

    public static int getTwo() {
        System.out.println("getTwo is called");
        return 2;
    }
}

Complex version of Ternary operation:

boolean b;
        int x = (int) (Math.random() * 1000);
        int y = (int) (Math.random() * 1000);
        int z = (int) (Math.random() * 1000);
//        x = 100;
//        y = 20;
//        z = 30;

        b = x < y ? x < z ? true : false : false;
        System.out.println(b);

        b = (x < y ? (x < z ? true : false) : false);
        System.out.println(b);

        b = (x < y && (x < z ? true : false));
        System.out.println(b);

Precedence. Evaluation Order:

int a = 6;
int b = 5;
int c = 10;
float rs = a + ++b * c / a * b;
System.out.println(rs);

Situation1:

int a = 6;
int b = 5;
int c = 10;

int rs = ++b * c / a * b;
System.out.println(rs);

Burada cavab 60 alinir. Cunki ilk once (++b) olur ve b = 6 olur. Sonra ise moterize olmadigi ucun

6 * 10 / 6 * 6 olur.

Situation2:

int a = 6;
int b = 5;
int c = 10;

int rs = b++ * c / a * b;
System.out.println(rs);

Burada ise cavab 48 alinir. Cunki 5 * 10 / 6 * 6 olur.

Situation3:

int a = 6;
int b = 5;
int c = 10;

int rs = a++ + ++b * c / a * b;
System.out.println(rs); 

Burada cavab 54 alinir. Cunki 6 + 6 * 10 / 7 *  6 olur.