Compilare: user.cpp: In function ‘int search_sum(int, int)’: user.cpp:18:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s1>=0 && i<N){ ^ user.cpp:27:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(K>lower && K<=upper) ^ user.cpp:27:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(K>lower && K<=upper) ^ user.cpp:29:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (K<=lower) ^ user.cpp:31:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(K>upper) ^ user.cpp: In function ‘int main()’: user.cpp:36:19: 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:33:1: warning: control reaches end of non-void function [-Wreturn-type] } ^