Compilare: user.cpp: In function ‘int main()’: user.cpp:39:10: warning: unused variable ‘a’ [-Wunused-variable] int n, a, b, i, x, y; ^ user.cpp:39:13: warning: unused variable ‘b’ [-Wunused-variable] int n, a, b, i, x, y; ^ user.cpp:40:23: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &n); ^ user.cpp:46:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d", &x, &y); ^