This document furnishes some examples of input and output in C++

Note on Namespaces:
If you are using a modern C++ complier you will need to bring
the 'cin', 'cout', 'endl' symbols into your namespace by
adding a statement like:
using namespace std;
or (perhaps better, since less inclusive) adding statements like:
using std::cin;
using std::cout;
using std::endl;
at the top of the file, after the #include <iostream.h>


Echoing the input to the output:

#include <iostream.h>  // This needs to be in all the following examples

	int ch;
	while (cin >> ch)
	{
		cout << ch;
	}


An alternative way of echoing the input to the output:

	int ch;
	while ((ch = cin.get()) != EOF)
	{
		cout.put(ch);
	}


Two alternatives for inputing a whole line (not just one word):

	const int SIZE = 80;
	int ch;
	char buffer[SIZE};
	cin.get(buffer, SIZE);
	cout << "The string read was: " << buffer << endl;
	cin >> ch;	// get the newline character which is still there

-------------------------------------------------------------------

	const int SIZE = 80;
	char buffer[SIZE};
	cin.getline(buffer, SIZE);
	cout << "The string read was: " << buffer << endl;
	// newline character has been removed automatically by getline()


Inputing an integer (with a check that an integer was read):

	int num;
	cin >> num;
	if (cin.good())
	{
		cout << "Read the integer " << num << endl;
	}
	else
	{
		cerr << "Failed to input an integer" << endl;
	}

An alternative way of inputing an integer (with a check):

	int num;
	cin >> num;
	if (cin.fail())
	{
		cerr << "Failed to input an integer" << endl;
	}
	else
	{
		cout << "Read the integer " << num << endl;
	}


Controlling the precision of floating point numbers on output:

	#include <math.h>
	double sqrt2 = sqrt(2.0);
	for (int places = 0; places < 10; places++)
	{
		cout.precision(places);
		cout << sqrt2  << endl;
	}

Controlling the field width of integer numbers on output:

	int num = 87;
	for (int places = 0; places < 10; places++)
	{
		cout.width(places);
		cout.fill('*');		// pad with *'s  (default is spaces)
		cout << "field width:" << places << "num:" << num  << endl;
	}