Compilare: main.cpp: In function 'int main()': main.cpp:33:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:49:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size() && nr.find(s[i])!=nr.end()) val=val*10+(s[i++]-'0'); ~^~~~~~~~~ main.cpp: In function 'int pr(char)': main.cpp:20:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:25:37: 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:26:39: 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); ^