Yes, I was talking about what is described in your resources. You can do this:
// define a floating-point literal in hex and print it in decimal
float x = 0x1p-8; // x = 1.0/256
printf("x = %g\n", x); // prints 0.00390625
// define a floating point literal in decimal and print it in various ways
float y = 0.3; // non-representable, rounded to closest float
printf("y = %g\n", y); // 0.3 (the %g format does some heuristics)
printf("y = %.10f\n", y); // 0.3000000119
printf("y = %.20f\n", y); // 0.30000001192092895508
printf("y = %a\n", f); // 0x1.333334p-2
