Compilare: user.cpp: In function ‘int main()’: user.cpp:80:18: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses] cin >> s + 1; ^ user.cpp:121:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < add.size(); k++) ^ user.cpp:124:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < multiply.size(); k++) ^