Power of “Primitive” C++ Bjarne Stroustrup Morgan Stanley, Columbia University www.Stroustrup.com Stroustrup - "Primitive" - CppCon 2020 1This year is different Stroustrup - "Primitive" - CppCon 2020 Observations • C++ is quite good at this • But not perfect, we’ll continue to improve it Stroustrup - "Primitive" - CppCon 2020 4 Alternative talk title: “The fun and frustrations of writing low-level code” fields cannot be known until run time • Maybe read at B, modify, and pass along to C Stroustrup - "Primitive" - CppCon 2020 5 First decide what you want aka Requirements analysis Message write read

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course, a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Prerequisites You need recent versions of the following programs to compile Agda: GHC:

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course, a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Prerequisites You need recent versions of the following programs to compile Agda: GHC:

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course, a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Prerequisites You need recent versions of the following programs to compile Agda: GHC:

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course, a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Prerequisites You need recent versions of the following programs to compile Agda: GHC:

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course, a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Installation There are several ways to install Agda: Using a released source package from

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course, a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Installation There are several ways to install Agda: Using a released source package from

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course, a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Installation There are several ways to install Agda: Using a released source package from

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course, a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Installation There are several ways to install Agda: Using a released source package from

of arithmetical operations the type (n : Nat) -> (PrimRoot n) consisting of functions computing primitive root in modular arithmetic. Of course a program of the above type will be more difficult to write number which is a primitive root. However, the difficulty can be compensated by the fact that the program is guaranteed to work: it cannot produce something which is not a primitive root. On a more mathematical example, a function of type (n : Nat) -> (PrimRoot n) is also a proof that every natural number has a primitive root. Prerequisites You need recent versions of the following programs to compile Agda: GHC: