Real variables: a large real number plus a small real number.

#include <stdio.h>
void main ()
{
     a float a, B;
     a = 1.23456e15;    // assigned to a real variable //
     B + a = 20;    // the value of a real variable plus 20 after // assign real variable b
     the printf ( "% = E a, E b =% \ n-", a, b);    // output a real variable exponentially, the value of b //
}