View Compilation Error

0_0_25155842_15563.cpp:5:1: error: 'map' does not name a type
 map<string, int> mp;
 ^
0_0_25155842_15563.cpp: In function 'int get_id(std::string)':
0_0_25155842_15563.cpp:8:9: error: 'mp' was not declared in this scope
     if(!mp[s]) mp[s] = id++;
         ^
0_0_25155842_15563.cpp:8:24: error: 'id' was not declared in this scope
     if(!mp[s]) mp[s] = id++;
                        ^
0_0_25155842_15563.cpp:9:12: error: 'mp' was not declared in this scope
     return mp[s];
            ^
0_0_25155842_15563.cpp: In function 'int main()':
0_0_25155842_15563.cpp:22:9: error: 'mp' was not declared in this scope
         mp.clear();
         ^