# spelled out number calculator

Bjarne Stroustrup “Programming Principles and Practice Using C++”
Chapter 4 Exercise 7
Using std_lib_facilities.h by Bjarne Stroustrup.

```//	Philipp Siedler
//	Bjarne Stroustrup's PP
//	Chapter 4 Exercise 7

#include "std_lib_facilities.h"

vector<string> numbers;

void initNumbers() {
numbers.push_back("zero");
numbers.push_back("one");
numbers.push_back("two");
numbers.push_back("three");
numbers.push_back("four");
numbers.push_back("five");
numbers.push_back("six");
numbers.push_back("seven");
numbers.push_back("eight");
numbers.push_back("nine");
}

int getNum() {
int vali = numbers.size();
string vals;

// getInt
if (cin >> vali) {
if (vali <= 10) {
return vali;
}
else {
error("Entered integer is too high. You entered: ", vali);
}
}

cin.clear();
// getString
string s = "noNumber";
cin >> vals;
for (int i = 0; i < numbers.size(); i++) {
if (numbers[i] == vals) {
return i;
s = vals;
}
}
if (s == "noNumber") {
error("Illegal entered number. You entered: ", vals);
}
}

int main()
try{

initNumbers();
int value1 = 0;
int value2 = 0;
char operat = ' ';

while (cin) {

cout << "Enter two intgeres followed by a operator seperated by spaces.\n";
//cout << "Enter one integer as digit or written out: \n";
value1 = getNum();

//cout << "Enter another integer as digit or written out: \n";
value2 = getNum();

//cout << "Enter an ooperator: \n";
cin >> operat;

if (operat == '+') {
cout << value1 << " " << operat << " " << value2 << " equals to: " << value1 + value2 << "\n";
}
if (operat == '-') {
cout << value1 << " " << operat << " " << value2 << " equals to: " << value1 - value2 << "\n";
}
if (operat == '/') {
cout << value1 << " " << operat << " " << value2 << " equals to: " << value1 / value2 << "\n";
}
if (operat == '*')
{
cout << value1 << " " << operat << " " << value2 << " equals to: " << value1 * value2 << "\n";
}
}

keep_window_open(".");
}

catch (runtime_error e) {	// this code is to produce error messages; it will be described in Chapter 5
cout << e.what() << '\n';
keep_window_open(".");	// For some Windows(tm) setups
}
catch (...) {	// this code is to produce error messages; it will be described in Chapter 5
cout << "exiting\n";
keep_window_open(".");	// For some Windows(tm) setups
}
```
```Output:
Enter two intgeres followed by a operator seperated by spaces.
two 3 +
2 + 3 equals to: 5
Enter two intgeres followed by a operator seperated by spaces.```

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