Language
C++
Compiler
gcc HEAD 14.0.0 20231229 (experimental)
Options
Don't Use Boost
C++2b(GNU)
no pedantic
$ g++ prog.cc -std=gnu++2b decltype demo
//int
auto i=0;
decltype(i) i2=i;
(typeid(i) == typeid(i2)) = true
//long
auto l=10l;
decltype(l) l2=l;
(typeid(l) == typeid(l2)) = true
//long long
auto ll=10ll;
decltype(ll) ll2=ll;
(typeid(ll) == typeid(ll2)) = true
//float
auto f=5.f;
decltype(f) f2=f;
(typeid(f) == typeid(f2)) = true
//double
auto d=5.;
decltype(d) d2=d;
(typeid(f) == typeid(f2)) = true
//vector<int>::iterator
auto itr=vec.begin();
decltype(itr) itr2=itr;
(typeid(itr) == typeid(itr2)) = true
//lambda
auto lam = [](){cout << "hello, world!";};
decltype(lam) lam2=lam;
(typeid(lam) == typeid(lam2)) = true
template <typename U, typename V>
auto add(U u, V v)->decltype(u+v) { return u+v; };
add<float,int>(3.5,10) = 13.5
Exit Code:
0