Compilare: user.cpp: In function ‘int eval()’: user.cpp:22:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(c<=s.size()) ^ user.cpp:24:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(c==s.size()||s[c]==')') {c++;return curr;} ^ user.cpp: In function ‘int main()’: user.cpp:46:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<changes.size();i++) ^ user.cpp: In function ‘int termen()’: user.cpp:18:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int eval()’: user.cpp:38:1: warning: control reaches end of non-void function [-Wreturn-type] } ^