I was recently trying out some code for an calculator, and i found one which worked..
But whatever i tried, this program would go off immediately after showing the answer on console. Please help me on this, i tried my best to actually make it stop. But it wouldnt work...
I'm using Visual Studio for the coding, If it is related to it, then inform me on it
#include <iostream>
#include <string>
#include <cctype>
#include<conio.h>
int expression();
char token() {
char ch;
std::cin >> ch;
return ch;
}
int factor() {
int val = 0;
char ch = token();
if (ch == '(') {
val = expression();
ch = token();
if (ch != ')') {
std::string error = std::string("Expected ')', got: ") + ch;
throw std::runtime_error(error.c_str());
}
}
else if (isdigit(ch)) {
std::cin.unget();
std::cin >> val;
}
else throw std::runtime_error("Unexpected character");
return val;
}
int term() {
int ch;
int val = factor();
ch = token();
if (ch == '*' || ch == '/') {
int b = term();
if (ch == '*')
val *= b;
else
val /= b;
}
else std::cin.unget();
return val;
}
int expression() {
int val = term();
char ch = token();
if (ch == '-' || ch == '+') {
int b = expression();
if (ch == '+')
val += b;
else
val -= b;
}
else std::cin.unget();
return val;
}
int main(int argc, char **argv) {
try {
std::cout << expression();
}
catch (std::exception &e) {
std::cout << e.what();
}
return 0;
}