Compilare: user.cpp: In function ‘int sub(int, int)’: user.cpp:26: warning: comparison between signed and unsigned integer expressions user.cpp:28: warning: comparison between signed and unsigned integer expressions user.cpp:32: warning: comparison between signed and unsigned integer expressions user.cpp:34: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:54: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘long long int’ user.cpp:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result