Compilare: main.cpp: In function 'int main()': main.cpp:71:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<postfix_st.size(); ++i) { ~^~~~~~~~~~~~~~~~~~ main.cpp: In function 'int get_priority(char)': main.cpp:19:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:23:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.in", "r", stdin); ^ main.cpp:24:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.out", "w", stdout); ^ main.cpp:26:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s\n", exp); ^ main.cpp:34:26: warning: 'res' may be used uninitialized in this function [-Wmaybe-uninitialized] int current_number = 0, res, a, b; ^~~