Compilare: user.cpp: In function ‘void add(BIG&, BIG&)’: user.cpp:43:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < B.size() || i < A.size() || t; i++, t /= 10) ^ user.cpp:43:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < B.size() || i < A.size() || t; i++, t /= 10) ^ user.cpp:45:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] int b = (i >= B.size() ? 0 : B[i]); ^ user.cpp:46:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i >= A.size()) ^ user.cpp: In function ‘void sub(BIG&, BIG&)’: user.cpp:55:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < A.size(); i++) ^ user.cpp:57:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] A[i] -= (i < B.size() ? B[i] : 0) + t; ^ user.cpp: In function ‘int main()’: user.cpp:85:9: warning: ‘lastj’ may be used uninitialized in this function [-Wmaybe-uninitialized] int lastj; ^