## Integers

You can use the hex, oct, and dec manipulators to stipulate that any character sequence input is to processed as a hexadecimal, octal, or decimal number.

int n;
cin >> oct >> n;

An input value of 10 will be interpreted as an octal, which corresponds to a decimal value of 8.

cin >> hex >> n;

Here, any input will be interpreted as a hexadecimal, enabling input such as f0a or -F7.

## Floating-Point Numbers

The >> operator interprets any input as a decimal floating-point number if the variable is a floating-point type, i.e. float, double, or long double.

The floating-point number can be entered in fixed point or exponential notation.

double x;
cin >> x;

The character input is converted to a double value in this case. Input, such as 123, -22.0, or 3e10 is valid.

## Demo

#include <iostream>
#include <iomanip>
using namespace std;
int main() // ww w. j a v a 2s . co m
{
int number = 0;
cout << "\nEnter a hexadecimal number: " << endl;
cin >> hex >> number; // Input hex-number
cout << "Your decimal input: " << number << endl;
// If an invalid input occurred:
cin.sync(); // Clears the buffer
cin.clear(); // Reset error flags
double x1 = 0.0, x2 = 0.0;
cout << "\nNow enter two floating-point values: " << endl;
cout << "1. number: ";
cin >> x1; // Read first number
cout << "2. number: ";
cin >> x2; // Read second number
cout << fixed << setprecision(2)
<< "\nThe sum of both numbers: "
<< setw(10) << x1 + x2 << endl;
cout << "\nThe product of both numbers: "
<< setw(10) << x1 * x2 << endl;
return 0;
}

## Result

## Exercise