Four-Operation Calculator
Programming Basics · Java
TASK
Problem
Read two integers `a`, `b` and an operator `+`, `-`, `*` or `/`. Print the integer result. For division, `b` is guaranteed to be non-zero.
EXAMPLE
Example
8 3 +
11
LIMITS
Constraints
|a|, |b| ≤ 10^9; for `/`, b != 0
LEARN
Theory for this problem
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The core idea of **Four-Operation Calculator** is to model the requested operation directly: Read two integers `a`, `b` and an operator `+`, `-`, `*` or `/`. Print the integer result. For division, `b` is guaranteed to be non-zero. The reference solution uses `Scanner` for input. Keep only the state needed for this result, choose numeric types that cover the stated bounds, and preserve the exact input/output contract. This makes the solution easier to verify on boundary cases and avoids unrelated work.
NEED HELP?
Hints
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['Follow the statement for **Four-Operation Calculator** literally and identify the smallest state needed to produce its output.', 'The reference solution relies on `Scanner` for input; test the smallest allowed input and one boundary case from the constraints.']
ANSWER
Solution
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// CodeMaster — Four-Operation Calculator
import java.util.*;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
long a = sc.nextLong();
long b = sc.nextLong();
char op = sc.next().charAt(0);
long result;
switch (op) {
case '+' -> result = a + b;
case '-' -> result = a - b;
case '*' -> result = a * b;
case '/' -> result = a / b;
default -> throw new IllegalArgumentException("Unsupported operator");
}
System.out.println(result);
}
}