Compilare: user.cpp: In function ‘int main()’: user.cpp:24:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<A.size(); i++) ~^~~~~~~~~ user.cpp:31:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (int (A[i])>=97 && int (A[i])<=122 && i<A.size()) ~^~~~~~~~~ user.cpp:33:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (A[i]==' ' && i<A.size()) ~^~~~~~~~~ user.cpp:36:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (int (A[i])>=48 && int (A[i])<=57 && i<A.size()) ~^~~~~~~~~ user.cpp:44:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (A[i]==' ' && i<A.size()) ~^~~~~~~~~ user.cpp:47:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (int (A[i])>=48 && int (A[i])<=57 && i<A.size()) ~^~~~~~~~~