Compilare: user.cpp: In function ‘int eval_op(int, int, char)’: user.cpp:18:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:49:54: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(expr, sizeof(expr), fopen("evaluare.in", "r")); ^