Compilare: user.cpp: In function ‘void input()’: user.cpp:117:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , &foo1 , &foo2 ) ; ^ user.cpp:118:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , &n , &m ) ; ^ user.cpp:121:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , &a[ i ].x , &a[ i ].y ) ; ^ user.cpp:132:66: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d%d" , &b[ i ].x , &b[ i ].y , &b[ i ].val ) ; ^ user.cpp: In function ‘int main()’: user.cpp:226:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "tower.in" , "r" , stdin ) ; ^ user.cpp:227:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "tower.out" , "w" , stdout ) ; ^