Write a program in c plus plus to read 2 numbers and an operator then calculate result defined of this operator?

Answer 1

#include<iostream>

#include<string>

#include<sstream>

unsigned input_num (std::string prompt)

{

unsigned id = 0;

while (1)

{

std::cout<<prompt<<": ";

std::string input="";

getline (std::cin, input);

std::stringstream ss (input);

if (ss>>id)

break;

std::cout<<"Invalid input.\n";

}

return (id);

}

char input_op (std::string ops)

{

char op = 0;

while (1)

{

std::cout<<"Enter an operator ("<<ops<<"): ";

std::string input="";

getline (std::cin, input);

std::stringstream ss (input);

if (ss>>op && ops.find (op) != std::string::npos)

break;

std::cout<<"Invalid input.\n";

}

return (op);

}

int main()

{

unsigned num1 = input_num ("Enter a number");

unsigned num2 = input_num ("Enter another number");

// division is invalid if num2 is zero

char op = input_op (num2?"+-*/":"+-*");

unsigned result = 0;

switch (op)

{

case ('+'): result = num1+num2; break;

case ('-'): result = num1-num2; break;

case ('*'): result = num1*num2; break;

case ('/'): result = num1/num2;

}

std::cout<<num1<<op<<num2<<'='<<result<<std::endl;

}