Compilare: user.c: In function ‘main’: user.c:57:13: warning: multi-character character constant [-Wmultichar] nr = '-1'; ^ user.c:57:8: warning: overflow in implicit constant conversion [-Woverflow] nr = '-1'; ^ user.c:13:8: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&n,&k); ^ user.c:18:8: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%s",c); ^