A simple input program
//Miles converted to kilometers.
#include <iostream.h>
const double m_to_k = 1.609;
inline double convert(double mi) {
return (mi * m_to_k);
}
main()
{
double miles;
do {
cout << "Input distance in miles: ";
cin >> miles;
cout << "\nDistance is " << convert(miles)
<< " km." << endl;
} while (miles > 0);
return (0);
}
const double m_to_k = 1.609;
The keyword const replaces some uses of the preprocessor command define to create named literals. Using this type
modifier informs the compiler that the initialized value of m_to_k cannot be changed. Thus, it makes m_to_k a
symbolic constant.
inline double convert(double mi) {
return (mi * m_to_k);
}
The new keyword inline specifies that a function is to be compiled as inline code, if possible. This avoids function call
overhead and is better practice than C's use of define macros. As a rule, inline should be done sparingly and
only on short functions. We will discuss inlining in a later module.
cin >> miles;
The input stream variable cin is the normal standard input. The input operator >>, called the get from or
extraction operator, assigns values from the input stream to a variable.
cout << "\nDistance is " << convert(miles) << " km." << endl;
The value placed in the standard input stream is passed to the convert() function, returned as the number of kilometers, and
then printed to the standard output stream.
