Summ

#include <cmath>
#include <iostream>
using namespace std;
int main() {
int num1,num2,ns,mod,result;
char operation;
cin << num1 << num2 <<ns << operation;
switch (ns) {
    case 10 :
        switch (operation) {
            case "+":
                result = num1 + num2;
            case "-":
                result = num1 - num2;
            case "*":
                result = num1 * num2;
            case "/":
                result = num1 / num2;
            default: cout << "Wrong Input";}
    case 8:
        switch (operation) {
            case "+":
            case "-":
            case "*":
            case "/":
            default: cout << "Wrong Input";}
    case 4:
        switch (operation) {
            case "+":
            case "-":
            case "*":
            case "/":
            default: cout << "Wrong Input";}
    case 2:
        switch (operation) {
            case "+":
            {
                int sub1,sub2,count;
                sub1 = num1%10;
                sub2 = num2%10;
                count = 1;
                while (sub1 > 0 || sub2>0)
                {
                    sub1 = sub1%10;
                    sub2 = sub2%10;
                    num1= ((sub1+sub2)%1)*pow(10,count);
                    count = ++count;
                }
                result = num1;
            }
            case "-":
            case "*":
            case "/":
            default: cout << "Wrong Input";}
    default: cout << "Wrong Input";
}
    \\ операции для двоичной
    \\ четв
    \\ восьмеричной
    \\ десятичной
    \\ смерть ибо я не знаю как это сделать


    cout << result;
    return 0;
}