The C keywords "float" and "double" are based on the tradition established a decade earlier by IBM System/360 of calling FP32 as "single-precision" and FP64 as "double-precision".
This IBM convention has been inherited by the IBM programming languages FORTRAN IV and PL/I and from these 2 languages it has spread everywhere.
The C language has taken several keywords and operators from IBM PL/I, which was one of the three main inspiration sources for C (which were CPL/BCPL, PL/I and ALGOL 68).
So "float" and "double" are really inherited by C from PL/I.
A feature that is specific to C is that it has changed the default format for constants and for intermediate values to double-precision, instead of the single-precision that was the default in earlier programming languages.
This was done with the intention of protecting naive users from making mistakes, because if you compute with FP32 it is very easy to obtain erroneous results, unless you analyze very carefully the propagation of errors. Except in applications where errors matter very little, e.g. graphics and ML/AI, the use of FP32 is more suitable for experts, while bigger formats are recommended for normal users.
This IBM convention has been inherited by the IBM programming languages FORTRAN IV and PL/I and from these 2 languages it has spread everywhere.
The C language has taken several keywords and operators from IBM PL/I, which was one of the three main inspiration sources for C (which were CPL/BCPL, PL/I and ALGOL 68).
So "float" and "double" are really inherited by C from PL/I.
A feature that is specific to C is that it has changed the default format for constants and for intermediate values to double-precision, instead of the single-precision that was the default in earlier programming languages.
This was done with the intention of protecting naive users from making mistakes, because if you compute with FP32 it is very easy to obtain erroneous results, unless you analyze very carefully the propagation of errors. Except in applications where errors matter very little, e.g. graphics and ML/AI, the use of FP32 is more suitable for experts, while bigger formats are recommended for normal users.