Compilare: user.cpp: In function ‘int main()’: user.cpp:52:10: warning: unused variable ‘start’ [-Wunused-variable] clock_t start, end; ^ user.cpp:52:17: warning: unused variable ‘end’ [-Wunused-variable] clock_t start, end; ^ user.cpp:53:9: warning: unused variable ‘time’ [-Wunused-variable] double time; ^ user.cpp:58:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &N); ^ user.cpp:60:39: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d", &I[i].A, &I[i].B); ^