What's the difference between float , double and long variables?

Question

I know an integer can hold a whole number, a float can hold a decimal number and an unsigned can hold only positive numbers. But what is the function of double and long double

Answer 1

Long is similar to int but has 8 bytes of storage and cannot have decimal point values, whereas float is of 4 bytes and can store decimal point values but with lower precision. But double on the other hand has 8 bytes of storage and can as well store decimal point values with higher precision.