There are no built-in functions for summation and difference in C language, and they are usually added and subtracted directly. If necessary, you can customize the addition and subtraction functions, such as:
intsum(inta，intb)
{
return+b；
}
intsub(inta，intb)
{
returna-b；
}
Extended data
Introduction of some mathematical functions of standard library in c language;
1) trigonometric function Sinkstein
2) Inverse trigonometric function: asinacosatan
3) Hyperbolic function: sinhcoshtanh
4) exp, an exponential function based on e.
5) natural logarithmic function: log
6) Logarithmic function based on 10: log 10.
7) Square root: sqrt
8) Absolute value: fab