Compilare: user.cpp: In function ‘int main()’: user.cpp:76: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:77: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:88: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result user.cpp:80: warning: ‘x’ may be used uninitialized in this function user.cpp:80: warning: ‘y’ may be used uninitialized in this function user.cpp:80: warning: ‘cst’ may be used uninitialized in this function