Why is it, that you have to use two lines like:

cin.ignore;

cin.ignore;

or one time:

cin.ignore(2);

to make the console window wait for a keypress.

One cin.ignore, doesn't seem to do the work

Code:

/**************************************************************
* This program sums the numbers in a user-specified range, *
* omitting the if test that sets the upper and lower bounds. *
**************************************************************/
#include <iostream>
using std::cin;
using std::cout;
using std::endl;
int main()
{
int Num_1;
int Num_2;
int Num_one = 0;
int Num_two = 0;
int Range = 0;
cout << "Exercise 1.20:" << endl << endl;
cout << "Enter two numbers !" << endl << endl;
cout << "Enter number one: ";
cin >> Num_one;
Num_1 = Num_one;
cout << "Enter number two: ";
cin >> Num_two;
Num_2 = Num_two;
if ( Num_1 < Num_2 )
for ( Num_one = Num_one ; Num_one <= Num_two ; ++Num_one )
{
Range += Num_one;
if ( Num_one >= Num_two )
{
cout << endl << "The sum of all numbers from " << Num_1
<< " to " << Num_2 << " is: " << Range << endl;
}
}
// else if ( Num_one > Num_two ) // This works, but I "haven't learned" this
// technique yet...
if ( Num_1 >= Num_2 )
for ( Num_two = Num_two ; Num_two <= Num_one ; ++Num_two )
{
Range += Num_two;
if ( Num_one <= Num_two )
{
cout << endl << "The sum of all numbers from " << Num_1
<< " to " << Num_2 << " is: " << Range << endl;
}
}
cout << endl << "Press [Enter] to exit... ;-)" << endl;
cin.ignore(2); // To make the console window, wait for a keypress !
return 0;
}