Compilare: user.cpp: In function ‘int Up_heap(int)’: user.cpp:48:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int Down_heap(int)’: user.cpp:66:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int Add_heap(int)’: user.cpp:70:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int Pop_front_heap()’: user.cpp:75:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘char nextch()’: user.cpp:13:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, BUF_SIZE, 1, fi); ^