Compilare: user.cpp: In function ‘void update(double)’: user.cpp:27: warning: suggest parentheses around ‘&&’ within ‘||’ user.cpp: In function ‘int main()’: user.cpp:37: warning: unused variable ‘k’ user.cpp:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:70: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result