View Compilation Error

0_0_18031098_24555.cpp: In function 'int main()':
0_0_18031098_24555.cpp:56:13: error: 'cout' was not declared in this scope
             cout << "0" << endl;
             ^
0_0_18031098_24555.cpp:56:28: error: 'endl' was not declared in this scope
             cout << "0" << endl;
                            ^
0_0_18031098_24555.cpp:68:9: error: 'cout' was not declared in this scope
         cout << L << endl;
         ^
0_0_18031098_24555.cpp:68:22: error: 'endl' was not declared in this scope
         cout << L << endl;
                      ^