#include <iostream> using namespace std; double sumNums(double num1, double num2); double subNums(double num1, double num2); double multNums(double num1, double num2); double divNums(double num1, double num2); int main() { char op; float num1, num2; cout << "Enter + for addition \nEnter - for subtraction \nEnter * for multiplication \nEnter / for division \nEnter O to show previous five operators \nEnter E to exit" << endl; cout << "\nChoose an option: "; cin >> op; cout << "Enter first number: "; cin >> num1; cout << "Enter the second number: "; cin >> num2; switch(op) { case '+': cout << "" << num1 << " + " << num2 << " = " << sumNums(num1, num2) << endl; break; case '-': cout << "" << num1 << " - " << num2 << " = " << subNums(num1, num2) << endl; break; case '*': cout << "" << num1 << " * " << num2 << " = " << multNums(num1, num2) << endl; break; case '/': cout << "" << num1 << " / " << num2 << " = " << divNums(num1, num2) << endl; break; case 'E': cout << "Thank you"; break; default: cout << "Select a valid menu option" << endl; break; } while(op != 'E') { cout << "\nEnter + for addition \nEnter - for subtraction \nEnter * for multiplication \nEnter / for division \nEnter O to show previous five operators \nEnter E to exit" << endl; cout << "\nChoose an option: "; cin >> op; cout << "Enter first number: "; cin >> num1; cout << "Enter the second number: "; cin >> num2; switch(op) { case '+': cout << "" << num1 << " + " << num2 << " = " << sumNums(num1, num2) << endl; break; case '-': cout << "" << num1 << " - " << num2 << " = " << subNums(num1, num2) << endl; break; case '*': cout << "" << num1 << " * " << num2 << " = " << multNums(num1, num2) << endl; break; case '/': cout << "" << num1 << " / " << num2 << " = " << divNums(num1, num2) << endl; break; case 'E': cout << "Thank you"; break; default: cout << "Select a valid menu option" << endl; break; } } return 0; } double sumNums(double num1, double num2) { double sum; sum = 0; sum = num1 + num2; return sum; } double subNums(double num1, double num2) { double dif; dif = 0; dif = num1 - num2; return dif; } double multNums(double num1, double num2) { double prod; prod = 0; prod = num1 * num2; return prod; } double divNums(double num1, double num2) { double quot; quot = 0; quot = num1 / num2; return quot; } ...

1. #include <iostream>
using namespace std;
double sumNums(double num1, double num2);
double subNums(double num1, double num2);
double multNums(double num1, double num2);
double divNums(double num1, double num2);
int main()
{
char op;
float num1, num2;
cout << "Enter + for addition nEnter - for subtraction
nEnter * for multiplication nEnter / for division nEnter O to
show previous five operators nEnter E to exit" << endl;

2. cout << "nChoose an option: ";
cin >> op;
cout << "Enter first number: ";
cin >> num1;
cout << "Enter the second number: ";
cin >> num2;
switch(op)
{
case '+':
cout << "" << num1 << " + " << num2 << " = "
<< sumNums(num1, num2) << endl;
break;
case '-':
cout << "" << num1 << " - " << num2 << " = "
<< subNums(num1, num2) << endl;

3. break;
case '*':
cout << "" << num1 << " * " << num2 << " = "
<< multNums(num1, num2) << endl;
break;
case '/':
cout << "" << num1 << " / " << num2 << " = "
<< divNums(num1, num2) << endl;
break;
case 'E':
cout << "Thank you";
break;
default:
cout << "Select a valid menu option" << endl;
break;
}

4. while(op != 'E')
{
cout << "nEnter + for addition nEnter - for
subtraction nEnter * for multiplication nEnter / for division
nEnter O to show previous five operators nEnter E to exit" <<
endl;
cout << "nChoose an option: ";
cin >> op;
cout << "Enter first number: ";
cin >> num1;
cout << "Enter the second number: ";
cin >> num2;
switch(op)
{
case '+':
cout << "" << num1 << " + " << num2 << " = "

5. << sumNums(num1, num2) << endl;
break;
case '-':
cout << "" << num1 << " - " << num2 << " = "
<< subNums(num1, num2) << endl;
break;
case '*':
cout << "" << num1 << " * " << num2 << " = "
<< multNums(num1, num2) << endl;
break;
case '/':
cout << "" << num1 << " / " << num2 << " = "
<< divNums(num1, num2) << endl;
break;
case 'E':
cout << "Thank you";
break;
default:
cout << "Select a valid menu option" << endl;
break;

6. }
}
return 0;
}
double sumNums(double num1, double num2)
{
double sum;
sum = 0;
sum = num1 + num2;
return sum;
}

7. double subNums(double num1, double num2)
{
double dif;
dif = 0;
dif = num1 - num2;
return dif;
}
double multNums(double num1, double num2)
{
double prod;
prod = 0;
prod = num1 * num2;
return prod;
}
double divNums(double num1, double num2)

8. {
double quot;
quot = 0;
quot = num1 / num2;
return quot;
}