Float and double are floating-point and double-precision respectively, representing decimals with different precision.
Float is a single-precision floating-point type, which can be accurate to six decimal places, 3.4x10 (-38) ~ 3.4x10 (+38).
Double is a double-precision floating-point type, which can be accurate to 12 decimal places,1.7x10 (-308) ~1.7x10 (+308).
Char is a single-byte character, from-(2 7) to 2 7-1,that is,-128 to 127. For unsigned characters, it is 0 to 2 8-1,that is, 0 to 255.
Hope to adopt