什么时候需要用delete,已经没有使用产生什么后果,
main.cpp程序代码:
#include<iostream> #include"student.hpp" using namespace std; int main(){ student *head,*stu; long del_num; cout<<"input records:"<<endl; head=creat(); print(head); cout<<endl<<"input the deleted number:"; cin>>del_num; head=del(head,del_num); print(head); cout<<endl<<"input the insert number:"; stu=new student; cin>>stu->num>>stu->score; while(stu->num!=0){ head=insert(head,stu); stu=new student; cin>>stu->num>>stu->score; } print(head); return 0; }
student.hpp
程序代码:
#include<iostream> using namespace std; struct student{ long num; float score; student *next; }; int n; student *creat(){ student *head; student *p1,*p2; n=0; p1=p2=new student; cin>>p1->num>>p1->score; head=NULL; while(p1->num!=0){ n=n+1; if(n==1)head=p1; else p2->next=p1; p2=p1; p1=new student; cin>>p1->num>>p1->score; } p2->next=NULL; return (head); } void print(student *head) { student *p; cout<<endl<<"Now,These"<<n<<"records are:"<<endl; p=head; if(head!=NULL) do{ cout<<p->num<<" "<<p->score<<endl; p=p->next; }while(p!=NULL); } student * del(student *head,long num) { student *p1,*p2; if(head==NULL) { cout<<"list null"<<endl;return (head); } p1=head; while(num!=p1->num&&p1->num!=NULL) { p2=p1; p1=p1->next; } if(num==p1->num){ if(p1==head)head=p1->next; else p2->next=p1->next; cout<<"delete:"<<num<<endl; n=n-1; } else cout<<"cannot find"<<num; return (head); } student *insert(student *head,student *stud) { student *p0,*p1,*p2; p1=head; p0=stud; if(head==NULL){ head=p0; p0->next=NULL; } else{ while((p0->num>p1->num)&&(p1->next!=NULL)){ p2=p1; p1=p1->next; } if(p0->num<=p1->num) { if(head==p1)head=p0; else p2->next=p0; p0->next=p1; } else{ p1->next=p0; p0->next=NULL; } n=n+1; return (head); } }
在mian程序里需要在最后加上 delete head;
delete stu;吗
自我感觉需要,但是程序运行并没有出错,已经教材书上也没有这样做
所以不解了,求解释