Compilare: user.c: In function ‘ultima_cifra’: user.c:52:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘main’: user.c:62:10: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(x,100,f); ^ user.c:70:14: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(x,100,f); ^ user.c:83:14: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(x,100,f); ^