base.cpp

C++ provides three manipulators, dec, oct, and hex, that format numbers in different bases or radixes for output. Note the following:

• The default output is decimal or base 10
• Order is important: hex << number not number << hex
• All three manipulators change one of the formatting flags; once changed, all numerical output will be in the new base until the base is changed by another manipulator or function

#include <iostream>
using namespace std;

int main()
{
	cout << 2749 << endl;		// decimal (base 10) output
	cout << dec << 2749 << endl;	// decimal (base 10) output
	cout << oct << 2749 << endl;	// octal (base 8) output
	cout << hex << 2749 << endl;	// hexadecimal (base 16) output

	cout << endl;
	cout.setf(ios::showbase);	// display output base

	cout << 2749 << endl;		// still in hexadecimal mode
	cout << dec << 2749 << endl;	// decimal (base 10) output
	cout << oct << 2749 << endl;	// octal (base 8) output
	cout << hex << 2749 << endl;	// hexadecimal (base 16) output

	return 0;
}

Output:

2749
2749
5275
abd

0xabd
2749
05275
0xabd