C++ Numeric Data Types

Numeric Types

Use int when you need to store a whole number without decimals, like 35 or 1000, and float or double when you need a floating point number (with decimals), like 9.99 or 3.14515.

int

#include <iostream>
using namespace std;
 
int main () {
  int myNum = 5000;
  cout << myNum;
  return 0;
}

float

#include <iostream>
using namespace std;
 
int main () {
  float myNum = 7.77;
  cout << myNum;
  return 0;
}

double

#include <iostream>
using namespace std;
 
int main () {
  double myNum = 11.99;
  cout << myNum;
  return 0;
}

float vs. double

The precision of a floating point value indicates how many digits the value can have after the decimal point. The precision of float is only six or seven decimal digits, while double variables have a precision of about 15 digits. Therefore it is safer to use double for most calculations.

Scientific Numbers

A floating point number can also be a scientific number with an “e” to indicate the power of 10:

Example:

#include <iostream>
using namespace std;
 
int main () {
  float f1 = 31e3;
  double d1 = 17E4;
  cout << f1 << "\n";
  cout << d1;
  return 0;
}

Output—->

31000
170000

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