0_0_14953209_10380.cpp: In function 'int main()': 0_0_14953209_10380.cpp:39:21: error: redeclaration of 'std::vector<int> b' vector<int> b; ^ 0_0_14953209_10380.cpp:37:21: note: 'std::vector<int> b' previously declared here vector<int> b; ^