Floating Point Data Types


The floating point data types are used to represent real numbers (i.e. numbers representable via a decimal expansion). Up to three different sizes of floating point numbers can be defined, as shown below.

float        //  32 bit
double       //  64 bit (internal 80 maybe)
long double  //  64 or 80 bit

It is guaranteed that:

precision of float <= precision of double <= precision of long double.

Floating Point Constants

A floating point constant consists of:

Either the integer or decimal part of the constant may be missing, but not both. Either the decimal point or the exponent may be missing, but not both.

Examples

double a,b,c;       // three uninitialized numbers
double d = 100.001; // a number holding 100.001
double e = 1e2;     // a number holding 100 = 1 x 10*10
double f = 1e-2;    // a number holding .01  - negative exponent
double g = .01;     // a number holding .01  - integer part missing
double h = 1.1e2;   // a number holding 110 - all parts present