exp2

exp2

---

Calculates the base 2 exponential of a number

 #include <math.h> double exp2 ( double x  ); float exp2f ( float x  ); long double exp2l ( long double x  ); 

The return value of the exp2( ) function is 2 raised to the power of the function's argument, or 2^x. If the result is beyond the range of the function's type, a range error occurs.

The base 2 exponential function exp2( ) is the inverse of the base 2 logarithm function, log2( ).

Example

 // The famous grains-of-rice-on-a-chessboard problem. // The sultan loses a chess game. The wager was one grain for square 1 // on the chessboard, then double the last number for each successive // square. How much rice in all? int squares = 64; long double gramspergrain = 0.0025L;    // A grain of rice weighs 25 mg. long double sum = 0.0L; for ( int i = 0; i < squares; i++ )     sum += gramspergrain * exp2l( (long double)i );   printf( "The sultan's wager costs him %.3Lf metric tons of rice.\n",           sum / 1000000.0L );             // A million grams per ton. 

This code produces the following output:

 The sultan's wager costs him 46116860184.274 metric tons of rice. 

See Also

exp( ), expm1( ), log( ), log1p( ), log2( ), log10( )