[C++] Checking User Input Against a List

[dodle]

In Python the keyword "in" could be used to check if a string (or other type) was in a list:

if mystring in mylist:
print "It is in the list"
else:
print "Not found in the list"

Is there a similar keyword in C++, or do I need to create a function to iterate through a list?

[soltanis]

Uh, maybe? There is no "in" keyword in C++ although with the joys of operator overloading there's a good chance some C++ library lets you do that. I'll let someone who actually knows C++ (or uh, more of it than I do) answer, and for my part I can tell you that in C, you will have to use a compound conditional statement (if, else if, else) (and C doesn't have a concept of lists).

[MadCow108]

there are the STL containers and algorithms
http://www.cplusplus.com/reference/stl/
http://www.cplusplus.com/reference/algorithm/

what you are looking for is:
find, bsearch, upper_bound, lower_bound or equal_range

also have a look at the map, which is a kind of dictionary (based on a btree and not a hashtable like in python)

your python code would translate to:


list<string> l;
..
list<string>::iterator res = find(l.begin(), l.end(), mystring);
if (res != l.end())
cout << "found" << endl;
else
cout << "not found" << endl;


the algorithm's work on all containers with an STL interface

[dodle]

Thanks madcow, that does just what I need it to. Thanks for the example as well.


#include <iostream>
#include <list>
#include <algorithm>
using namespace std;

int main()
{
string mystring;
list<string> mylist;
mylist.push_back("Hello");
mylist.push_back("World");

cout << "Type Something: ";
getline(cin, mystring);

list<string>::iterator get = find(mylist.begin(), mylist.end(), mystring);
if (get != mylist.end())
cout << mystring << " found in list." << endl;
else
cout << mystring << " not found." << endl;

return 0;
}