scc 2+2 4
Simple IO
Bar-print
Instead of C++ std::cout printing, SCC uses so called bar-print.
Below are bar-print statements with equivalent code in comments:
_ x; // cout << x; __ x; // cout << x << endl; __ x << y; // cout << x << y << endl; __ x, y; // cout << x << " " << y << endl;
OI - Generic ostream_iterator
Standard library includes std::ostream_iterator. Unlike std::cout it accept only one specific type (specified at construction time) and it is not pre-defined object. So to use it with STL algorithms, you need call its quite verbose constructor.
Let say we have vector<int> V; and set<string> S; and we want copy these to std::cout. With standard library:
copy(V.begin(), V.end(), ostream_iterator<int>(cout, " ")); copy(S.begin(), S.end(), ostream_iterator<int>(cout, " "));
Include print.h defines oi object, which is similarly to std::cout, can work with any type and is pre-defined. With oi, above example will be:
copy(V.begin(), V.end(), oi); copy(S.begin(), S.end(), oi);
Assigning a container to oi is equivalent to doing std::copy, so above example we could have also written as:
oi = V; oi = S;
Containers Printing
Any STL container can be also printed without oi. You can just send it to std::cout or to bar-print.
In comments is equivalent code:
vint C {1,2,3}; __ C; // vector<int> C{1,2,3};
// cout << "{";
// for(auto it=C.begin(); it!=C.end()-1; it++)
// cout << *it << ", ";
// if(!C.empty()) cout << C.back();
// cout << "}\n";
// prints: {1, 2, 3}
int C[] {1,2,3}; __ C; // {1,2,3}
array<int,3> C {1,2,3}; __ C; // {1,2,3}
tuple<int,int> C {1,2}; __ C; // ⟨1, 2⟩
map<int,int> C {{1,1},{2,2}}; __ C; // {⟨1,1⟩, ⟨2,2⟩}
vector<vint> C {{1,1},{2,2}}; __ C; // {{1, 1}, {2, 2}}
Object IN
Pre-defined object in can be used as initialiser. When a value is read from in, it is acquired from std::cin.
int i(in); // int i; cin >> i; float x = 1.1 + float(in); // float y; cin >> y; float x = 1.1 + y;
|
Object in does not check for EOF. With scalar objects use only in context where you can ignore or do not expect EOF. |
If a container have non-zero length, we can directly input from std::cin without object in:
vint V(10); // vector<int> V(10); cin >> V; // for(size_t i=0; i<V.size(); i++) cin >> V[i];
Object in can be used to input container too, but we need somehow to tell it how many elements needs to be read.
If container have zero length, we tell object in how many object to read:
vint V = in(10);
Google CodeJam and FaceBook Hackercup often have input format to input an array where first goes a number (N) followed by N elements of an array. To read it, we can use:
int N(in); // int N; cin >> N; vint V = in(N); // vector<int> V(N); for(int i=0; i<N; i++) cin >> V[i];
Or even shorter:
vint V = in(in); // 1st will be evaluated 'in' in parenthesis, 2nd - 'in.operator()()'
If container have zero length (is empty) and we didn’t specified how many elements to read, container is filled up until EOF.
echo 1 2 3 | scc 'vint V = in; V' // Note: we can not use: vint V(in);
{1,2,3}
print.h standalone use
File print.h can be used as standalone, independent include.
#include <print.h>
int main() {
__ "hello world";
}
Files simple.h, cj.h and stl.h can also be used independently.