Compilare: user.cpp: In function ‘int prime(int)’: user.cpp:7:11: warning: unused variable ‘k’ [-Wunused-variable] int i,k; ^ user.cpp: In function ‘int main()’: user.cpp:25:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:28:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&v[i]); ^