C Numeric Data Types
Numeric Types
Use int when you need to store a whole number without decimals, like 35 or
1000, and float or double when you need a
floating point number (with decimals), like 9.99 or 3.14515.
float vs. double
The precision of a floating point value indicates how many digits the value can have
after the decimal point.
The precision of float is six or seven
decimal digits, while double variables have a precision
of about 15 digits. Therefore, it is often safer to use double for most
calculations - but note that it takes up twice as much memory as float (8
bytes vs. 4 bytes).
Scientific Numbers
A floating point number can also be a scientific number with an "e" to indicate the power of 10: