Compilare: user.cpp: In function ‘int recursiv(int)’: user.cpp:29:21: warning: for increment expression has no effect [-Wunused-value] for (j=k+1;j++;j<=n) ^ user.cpp: In function ‘int main()’: user.cpp:38:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:40:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%ld",&a[i]); ^ user.cpp:43:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%ld",&x); ^