Compilare: user.cpp: In function ‘int main()’: user.cpp:185: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:194: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘int valid(int, int&)’: user.cpp:41: warning: ‘y1’ may be used uninitialized in this function user.cpp:41: warning: ‘y2’ may be used uninitialized in this function user.cpp:41: warning: ‘x1’ may be used uninitialized in this function user.cpp:41: warning: ‘x2’ may be used uninitialized in this function