# BasicCalculation

``````import java.util.Scanner;

// for, foreach, if/else-if, switch, array, 2D array
public class BasicCalculation {

public static Scanner scan = new Scanner(System.in);

// calc (using if/else-if)
public static int calc(int x, int y, char op) {
if (op == '+') return x + y;
else if (op == '-') return x - y;
else if (op == '*') return x * y;
else if (op == '/') return x / y;
else {
return 0;
}
}

// calc2 (using switch)
public static int calc2(int x, int y, char op) {
switch(op) {
case '+': return x + y;
case '-': return x - y;
case '*': return x * y;
case '/': return x / y;
default:
return 0;
}
}

// get user input op[+,-,*,/]
static public char getUserInputOp() {
char value = '\0';
do {
System.out.printf("Please enter the operator [+,-,*,/]: ");
try {
value = scan.next().charAt(0);
System.out.println("value=" + value);
}
catch (Exception e) {
scan.next();
continue;
}
} while (value != '+' && value != '-' && value != '*' && value != '/');
return value;
}

public static void main(String[] args) {
// for
for (int i = 0; i < 5; i++) {
System.out.println("i=" + i);
}
// while
int j = 0;
while (j < 5) {
System.out.println("j=" + j);
j++;
}
// do-while
int k = 0;
do {
System.out.println("k=" + k);
k++;
} while (k < 5);
// break (0~4)
int x = 0;
while (true) {
if (x >= 5) break;
System.out.println("x=" + x);
x++;
}
// continue (0~4)
int y = 0;
while (y < 5) {
y++; // (1~5)
if (y % 2 == 1) // 홀수
continue;
System.out.println("y=" + y); // 짝수만 출력
}
// for-each
x = scan.nextInt();
y = scan.nextInt();
char[] ops = {'+', '-', '*', '/', '^'}; // char array
for (char op : ops) {
int z = calc(x, y, op);
System.out.printf("z = %d %s %d = %d\n", x, op, y, z);
}
// 2D array
int[][] numbers = {{49, 57}, {36, 29}, {88, 66}};
for (char op: ops) {
for (int i = 0; i < numbers.length; i++) {
int r = calc2(numbers[i][0], numbers[i][1], op);
System.out.printf("r = %d %c %d = %d\n",
numbers[i][0], op, numbers[i][1], r);
}
}
// user input