View Compilation Error

0_0_30325646_30774.cpp: In function 'void dfs(int, int, int, int)':
0_0_30325646_30774.cpp:15:9: error: 'cout' was not declared in this scope
         cout<<"+"<<b[i];
         ^
0_0_30325646_30774.cpp:17:9: error: 'cout' was not declared in this scope
         cout<<b[i];   
         ^
0_0_30325646_30774.cpp:19:8: error: 'cout' was not declared in this scope
        cout<<endl;
        ^
0_0_30325646_30774.cpp:19:14: error: 'endl' was not declared in this scope
        cout<<endl;
              ^
0_0_30325646_30774.cpp: In function 'int main()':
0_0_30325646_30774.cpp:29:12: error: 'cin' was not declared in this scope
     while((cin>>n>>len)&&len){
            ^
0_0_30325646_30774.cpp:32:9: error: 'cout' was not declared in this scope
         cout<<"Sums of "<<n<<":"<<endl;
         ^
0_0_30325646_30774.cpp:32:35: error: 'endl' was not declared in this scope
         cout<<"Sums of "<<n<<":"<<endl;
                                   ^