Fixed form, Scientific form and Precision setting for floating point numbers

Sometimes we want to output the floating point numbers in fixed or scientific form and sometimes with fixed precision so as to align all the output. The following program is an example to demonstrate that:

//Program tested on Microsoft Visual Studio 2008 - Zahid Ghadialy
//This example shows how to output floating point numbersin fixed and
#include<iostream>

using namespace std;

int main()
{
  float number = 123.456;

  cout << "number in fixed form = " << number << endl; //default is fixed
  cout << "number in scientific form = " << scientific << number << endl;
  cout.precision(2);
  cout << "number in fixed form with precision 2 = " << fixed << number << endl; //here the format was scientific
  cout.precision(3);
  cout << "number in fixed form with precision 3 = " << number << endl;
  cout.precision(4);
  cout << "number in fixed form with precision 4 = " << number << endl;
  cout.precision(5);
  cout << "number in fixed form with precision 5 = " << number << endl;

  return 0;
}

The output is as follows:

Printing out leading 0's (or any other charachters)

This is a simple example to print out leading zeroes or any charachters when printing out numbers. The main manipulator function needed is the set field width that will set the width of the field.

//Program tested on Microsoft Visual Studio 2008 - Zahid Ghadialy
//This example shows how to print leading 0's in the output

#include<iostream>
#include<iomanip>

using namespace std;

int main()
{
  int number = 123;

  cout<< "number = "<< number << endl;

  cout<< "number = "<< setw(2) << setfill('0') << number << endl;
  cout<< "number = "<< setw(3) << setfill('0') << number << endl;
  cout<< "number = "<< setw(4) << setfill('0') << number << endl;
  cout<< "number = "<< setw(5) << setfill('0') << number << endl;
  cout<< "number = "<< setw(10) << setfill('0') << number << endl;

  cout<< endl;
  cout<< "number = "<< setw(5) << setfill('x') << number << endl;

  cout<< endl;
  number = 0;
  cout<< "number = "<< setw(5) << setfill('x') << number << endl;

  return 0;
}

The output is as follows: