A null pointer benefit explicitly points to no legitimate locale. Dereferencing a null pointer value is undefined, frequently causing a segmentation fault. Null pointer values are handy for indicating Distinctive circumstances which include no "following" pointer in the ultimate node of the joined checklist, or as an error indicator from http://jaidencrfqy.timeblog.net/3210457/the-greatest-guide-to-r-programming-assignment-help