Compilare: user.cpp: In function ‘int main()’: user.cpp:22:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<str.length(); i++) ^ user.cpp:37:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<str.length(); i++) ^ user.cpp:65:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<=num[nr].length(); i++) ^ user.cpp:47:11: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] nr=a+b; ^ user.cpp:47:11: warning: ‘a’ may be used uninitialized in this function [-Wmaybe-uninitialized]