Compilare: user.cpp: In function ‘int find(int)’: user.cpp:21: warning: comparison between signed and unsigned integer expressions user.cpp:25: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int add(int)’: user.cpp:36: warning: no return statement in function returning non-void user.cpp: In function ‘int del(int)’: user.cpp:40: warning: comparison between signed and unsigned integer expressions user.cpp:44: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:52: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:53: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:55: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:58: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result