e-notation basically 2.0e20(or AeN) represents 2.0 * 10^20..

#include
#include

int main(void)
{
float a,b;
b = (2.0*pow(10,20)) + 1.0;//2.0e20 Can be expressed as 2.0 * 10^20
printf(“Value of b is %f\n”,b);

float c = 2.0e20;
printf(“Value of c is %f\n”,c);

a = b – (2.0*pow(10,20))/*c*/;//if I replace the exp with var c result changes to 0.0000….
printf(“Value of %f – %f = %f \n”,b,c,a);//Result seems lil Strange

return 0;

}

=============output=================
for the code in question
[root@linuxstation asgmt]# ./fourteen
./fourteen
Value of b is 200000004008175468544.000000
Value of c is 200000004008175468544.000000
Value of 200000004008175468544.000000 – 200000004008175468544.000000 = 4008175468544.000000

+++++++++++++output+++++++++++++++++++
when I replace the a = b – c ;

[root@linuxstation asgmt]# make fourteen
make fourteen
cc fourteen.c -o fourteen
[root@linuxstation asgmt]# ./fourteen
./fourteen
Value of b is 200000004008175468544.000000
Value of c is 200000004008175468544.000000
Value of 200000004008175468544.000000 – 200000004008175468544.000000 = 0.000000
[root@linuxstation asgmt]#