ed.cpp: In function 'int main()': ed.cpp:6: error: 'nullptr' was not declared in this scope ed.cpp:38: error: 'struct std::string' has no member named 'back' ed.cpp:39: error: 'struct std::string' has no member named 'pop_back' ed.cpp:47: error: 'struct std::string' has no member named 'pop_back' ed.cpp:52: error: 'stoi' was not declared in this scope ed.cpp:58: error: expected initializer before ':' token ed.cpp:61: error: expected primary-expression before 'return' ed.cpp:61: error: expected ')' before 'return' ed.cpp:22: warning: label 'right_insert' defined but not used