2.7.1. A. Arithmetic Operators

Operators are used to perform operations on variables and values. Java provides several categories.

Arithmetic operators are symbols in Java that perform mathematical operations such as addition, subtraction, multiplication, division, and modulus. These operators are crucial for doing calculations within a program. They act on numerical values, which can be constants or variables.

Think of arithmetic operators like the basic functions of a calculator. Just like you can add, subtract, multiply, and divide numbers on a calculator, you can do the same in a Java program using these operators.

Operator: +
Use: Addition
Example: a + b

Example in code:
int a = 10, b = 3;
System.out.println(a + b); // 13

The addition operator (+) combines two values. In the example above, when we add the values of 'a' (10) and 'b' (3), the result is 13. The System.out.println function then prints this result to the console.

Imagine you are at a grocery store. If you buy an apple for $10 and a banana for$3, the total cost you would pay is the sum of both, which is $13.

Operator: -
Use: Subtraction
Example: a - b

Example in code:
System.out.println(a - b); // 7

The subtraction operator (-) takes two numbers and subtracts the second from the first. For example, if 'a' is 10 and 'b' is 3, 'a - b' results in 7, as printed by the System.out.println method.

Think of when you have $10 and you spend$3. You subtract your spending from your total amount. Thus, you will have $7 left.

Operator: *
Use: Multiplication
Example: a * b

Example in code:
System.out.println(a * b); // 30

The multiplication operator (*) calculates the product of two numbers. In our example, if 'a' is 10 and 'b' is 3, then 'a * b' equals 30, which is printed to the console.

If you buy 3 bags of apples and each bag costs $10, the total cost is calculated by multiplying the number of bags by the cost per bag, giving you$30.

Operator: /
Use: Division
Example: a / b

Example in code:
System.out.println(a / b); // 3

The division operator (/) divides one number by another. In our context, dividing 10 by 3 gives a result of 3. In Java, when both numbers are integers, the result is also an integer, dropping any decimal part.

If you have 10 cookies and want to share them equally among 3 friends, each friend would get 3 cookies, with one cookie remaining unshared. This illustrates integer division.

Operator: %
Use: Modulus (remainder)
Example: a % b

Example in code:
System.out.println(a % b); // 1

The modulus operator (%) gives the remainder after dividing one number by another. In this case, 10 divided by 3 results in a quotient of 3 with a remainder of 1. Thus, 'a % b' produces 1.

Returning to the cookie example: If you try to equally distribute 10 cookies among 3 friends, each friend gets 3 cookies, and you have 1 cookie left over. This remaining cookie is the 'remainder' from the division.

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