Number of significant digits for a floating point type

Question

The description for type float in C mentions that the number of significant digits is 6. However,

float f = 12345.6;

Answer 1

The problem here is that you cannot assure a number can be stored in a float. You need to represent this number with mantissa, base and exponent as IEEE 754 explains. The number printf(...) shows you is the real float number that was stored. You can not assure a number of significant digits in a float number.