My program is written in C++.
#include <iostream> #include <string> #include <map> using namespace std; class Details { int x; int y; }; typedef std::map<string, Details> Det; Det det; Details::Details(int p, int c) { x = p; y = c; } int main(){ det.clear(); insertNew("test", 1, 2); cout << det["test"] << endl; return 0; } I want to print the value of a key with the simplest way. Eg det["test"] fails to compile. How to I print values (1,2) for (x,y) that correspond to key "test"?
My best guess is that you have no default or copy constructor in your Obj (you don't have any in the code you posted, but I assume you have one that takes two integers). You've also got a typo in the catalog.insert() line. Here is what worked for me, using your code:
class Obj { public: Obj() {} Obj(int x, int y) : x(x), y(y) {} int x; int y; }; int main (int argc, char ** argv) { std::map<std::string, Obj> catalog; catalog.insert(std::map<std::string, Obj>::value_type("test", Obj(1,2))); std::cout << catalog["test"].x << " " << catalog["test"].y << std::endl; return 0; } 
operator[] multiple times for the same value can severely degrade performance.Create an operator<< for your class Obj and then you can do something like std::cout << catalog["test"]; (I'm assuming that the missing parens in the insert call are just a copy-paste-o).
I've changed a bit your code.
#include <map> #include <iostream> #include <string> using namespace std; class Obj { public: Obj( int in_x, int in_y ) : x( in_x ), y( in_y ) {}; int x; int y; }; int main() { std::map< string, Obj* > catalog; catalog[ "test" ] = new Obj(1,2); for( std::map<string, Obj*>::iterator i=catalog.begin(); i != catalog.end(); ++i ) { cout << "x:" << i->second->x << " y:" << i->second->y << endl; } } Given these types:
class Obj { int x; int y; }; std::map<string, Obj> catalog; Given a populated catalog object:
for(auto ob = catalog.begin(); ob != catalog.end(); ++ob) { cout << ob->first << " " << ob->second.x << " " << ob->second.y; } 