Compilare: user.cpp: In function ‘int search_sum(int, int)’: user.cpp:16:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s1>=0 && i<N){ ^ user.cpp:21:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(up<N) ^ user.cpp: In function ‘int main()’: user.cpp:37:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<N;i++) ^ user.cpp: In function ‘int search_sum(int, int)’: user.cpp:34:1: warning: control reaches end of non-void function [-Wreturn-type] } ^