Compilare: user.cpp: In function ‘int query(int)’: user.cpp:98:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ant+i<env.size() && t>env[ant+i].x) ^ user.cpp: In function ‘int main()’: user.cpp:121:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<ls.size(); ++i) { /// Select 'lower envelope' lines ^ user.cpp:131:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<stk.size(); ++i) { /// Make 'lower envelope' ^ user.cpp:108:15: warning: unused variable ‘a’ [-Wunused-variable] int n, q, a, b, t; ^ user.cpp:108:18: warning: unused variable ‘b’ [-Wunused-variable] int n, q, a, b, t; ^ user.cpp: In function ‘void Parser::start()’: user.cpp:31:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vmin.in", "r", stdin); ^ user.cpp:32:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vmin.out", "w", stdout); ^ user.cpp:33:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, BMAX, stdin); ^ user.cpp: In function ‘char Parser::nextch()’: user.cpp:15:40: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, BMAX, stdin); ^