CLI calculator that performs computations on one line.

Calc.java

import java.text.NumberFormat;
import java.util.Locale;
import java.util.Scanner;

public class ConsoleCalc {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String line = sc.nextLine();

		scanNumbers(line);
		sc.close();
	}

	public static int containsOperator(String line) {
		for (int i = 0; i < line.length(); i++) {
			if (line.charAt(i) == '+') {
				return 0;
			} else if (line.charAt(i) == '-') {
				return 1;
			} else if (line.charAt(i) == '*') {
				return 2;
			} else if (line.charAt(i) == '/') {
				return 3;
			} else if (line.charAt(i) == '^') {
				return 4;
			}
		}
		return 5;
	}

	public static void scanNumbers(String line) {
		int a = 0;
		int b = 0;
		int endIndex = 0;
		String tempA = "", tempB = "";
		
		for (int i = 0; i < line.length(); i++) {
			if (line.charAt(i) != ' ' && line.charAt(i) != '+' && line.charAt(i) != '-' && line.charAt(i) != '*' && line.charAt(i) != '/' && line.charAt(i) != '^') {
				tempA = tempA.concat(Character.toString(line.charAt(i)));
				a = Integer.parseInt(tempA);
				endIndex = i;
				
			} else {
				break;
			}
		}
		
		for (int ii = endIndex+1; ii < line.length(); ii++) {
			if (line.charAt(ii) != ' ' && line.charAt(ii) != '+' && line.charAt(ii) != '-' && line.charAt(ii) != '*' && line.charAt(ii) != '/' && line.charAt(ii) != '^') {
				tempB = tempB.concat(Character.toString(line.charAt(ii)));
				b = Integer.parseInt(tempB);
			}
		}
		
		if (containsOperator(line) == 0) {
			System.out.println("= " + NumberFormat.getNumberInstance(Locale.US).format(add(a, b)));
		} else if (containsOperator(line) == 1) {
			System.out.println("= " + NumberFormat.getNumberInstance(Locale.US).format(subtract(a, b)));
		} else if (containsOperator(line) == 2) {
			System.out.println("= " + NumberFormat.getNumberInstance(Locale.US).format(multiply(a, b)));
		} else if (containsOperator(line) == 3) {
			System.out.println("= " + NumberFormat.getNumberInstance(Locale.US).format(divide(a, b)));
		} else if (containsOperator(line) == 4) {
			System.out.println("= " + NumberFormat.getNumberInstance(Locale.US).format(pow(a, b)));
	}
		
		main(null);
	}

	public static int add(int a, int b) {
		return a + b;
	}

	public static int subtract(int a, int b) {
		return a - b;
	}

	public static int multiply(int a, int b) {
		return a * b;
	}
	
	public static int divide(int a, int b) {
		return a / b;
	}
	
	public static int pow(int a, int b) {
		return (int)Math.pow(a, b);
	}
}