help with word input

[oliveoil]

i currently use visual studio 2019 compiler and i want to be able to input a word as a answer to std::cin. for example a calculator that you can say "division" into to input field which the code will then see and use the proper math function.

[MikeyBoy]

This tutorial will explain how to read user input from the command line:

http://www.cplusplus.com/doc/tutorial/basic_io/

And there's nothing Windows-specific about this question. You'd be better off moving it to the Beginners forum.

[seeplus]

You mean something like this for math functions?

#include <iostream>
#include <algorithm>
#include <string>

double getNum(const std::string& promp) {
	double no {};

	while ((std::cout << promp) && !(std::cin >> no)) {
		std::cout << "Invalid number\n";
		std::cin.clear();
		std::cin.ignore(1000, '\n');
	}

	return no;
}

int main()
{
	enum class Opers { Quit = 0, Add, Subtract, Multiply, Divide };

	struct s_ops {
		std::string name;
		Opers op;
	};

	const s_ops Ops[] {{"quit", Opers::Quit}, { "add", Opers::Add }, {"subtract", Opers::Subtract}, {"multiply", Opers::Multiply}, {"divide", Opers::Divide}};

	double next {}, sum {getNum("Enter first number: ")};
	std::string oper;
	auto fnd {std::begin(Ops)};

	do {
		do {
			std::cout << "Enter operator as a word (";
			for (const auto& o : Ops)
				std::cout << o.name << ' ';

			std::cout << "): ";
			std::cin >> oper;

			fnd = std::find_if(std::begin(Ops), std::end(Ops), [&oper](const auto& i) {return i.name == oper; });
			if (fnd != std::end(Ops)) break;
			else
				std::cout << "Invalid operator name entered\n";

		} while (true);

		if (fnd->op != Opers::Quit) {
			next = getNum("Enter next number: ");

			switch (fnd->op) {
				case Opers::Add: sum += next; break;
				case Opers::Subtract: sum -= next; break;
				case Opers::Multiply: sum *= next; break;
				case Opers::Divide: sum /= next; break;
			}
			std::cout << "Result is " << sum << '\n';
		} else break;
	} while (true);
}

[lastchance]

#include <iostream>
#include <string>
#include <cctype>
#include <set>
using namespace std;

string tolower( string s ){ for ( char &c : s ) c = tolower( c );   return s; }

int main()
{
   const set<string> ops{ "add", "subtract", "multiply", "divide" };
   double a, b, result;
   string op;
   cout << "Enter calculation as A op B, where op is one of add, subtract, multiply, divide: ";
   cin >> a >> op >> b;
   if ( ops.find( tolower( op ) ) == ops.end() )
   {
      cout << "Invalid operation\n";
   }
   else
   {
      switch( tolower( op[0] ) )
      {
         case 'a':   result = a + b;   break;
         case 's':   result = a - b;   break;
         case 'm':   result = a * b;   break;
         case 'd':   result = a / b;   break;
      }
      cout << result << '\n';
   }
}

Enter calculation as A op B, where op is one of add, subtract, multiply, divide: 56.9 divide 3.2
17.7812

[lastchance]

#include <iostream>
#include <string>
#include <cctype>
#include <map>
using namespace std;

string tolower( string s ){ for ( char &c : s ) c = tolower( c );   return s; }

int main()
{
   #define FN []( double a, double b )
   map<string,double (*)( double, double )> ops{
      { "add"     , FN{ return a + b; } },
      { "subtract", FN{ return a - b; } },
      { "multiply", FN{ return a * b; } },
      { "divide"  , FN{ return a / b; } } };

   double a, b;
   string op;
   cout << "Enter calculation as A op B, where op is one of add, subtract, multiply, divide: ";
   cin >> a >> op >> b;
   op = tolower( op );
   if ( ops.count( op ) ) cout << ops[op]( a, b ) << '\n';
   else                   cout << "Invalid operation\n";
}

Enter calculation as A op B, where op is one of add, subtract, multiply, divide: 12 divide 7
1.71429