1. How to make cin faster?
std::ios_base::sync_with_stdio(false);
2. An example of using <vector>
#include <iostream>
#include <vector>
#include <algorithm> // sort
int main ()
{
std::vector<int> V;
int x;
while (std::cin>>x) {
V.push_back(x);
}
for (auto t : V) std::cout<<" "<< t;
std::cout << "\n";
std::sort(V.begin(), V.end());
for (auto t : V) std::cout<<" "<< t;
std::cout << "\n";
}
3. An example of using <queue>
#include <iostream>
#include <algorithm>
#include <queue>
#include <string>
// Queueing
using namespace std;
int main()
{
string s;
queue<string> q;
while (cin >> s) {
if (s=="Push") {
cin >> s;
q.push(s);
}
else if (s=="Pop") {
if (q.size()>0)
q.pop();
}
else if (s=="Front") {
if (q.size()==0)
cout << "empty\n";
else
cout<<q.front()<<"\n";
}
}
}
4. An example of using <stringstream>
#include <string>
#include <iostream>
#include <sstream> // std::stringstream
int main () {
std::stringstream ss;
ss << "Hello " << 123;
std::string s = ss.str();
std::cout << s << '\n';
}
5. An example of using <set>
#include <iostream>
#include <set>
int main()
{
std::set<int> S = {1, 2, 3, 4};
auto search = S.find(2);
if(search != S.end()) {
std::cout << (*search) << '\n';
}
else {
std::cout << "Not found\n";
}
}
6. An example of using <stack>
#include <stack>
#include <iostream>
int main()
{
std::stack<int> s;
s.push( 3 ); s.push( 6 );
s.push( 18 );
std::cout<<s.size()<<" elements\n";
std::cout<<"Top: "<< s.top()<< "\n";
s.pop();
std::cout<<s.size()<<" elements\n";
}
7. An example of getline()
#include <string>
#include <iostream>
int main()
{
std::string name;
std::cout << "What is your name? ";
std::getline(std::cin, name);
std::cout << "Hello "<< name<< "\n";
}
8. An example of using <map>
#include <iostream>
#include <string>
#include <map>
#include <utility> // make_pair
int main()
{
std::map<std::string, int> ID;
ID.insert(std::make_pair("Tom", 123));
std::cout << ID["Tom"] << "\n";
}