初学链表，加深自己对链表的认识与理解

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
typedef struct student
{long num;char name[10];int C;int English;int Math;int sum;struct student *next; 
}Student;
//********************************************
Student *InitStudent()
{Student *p;p=(Student*)malloc(sizeof(Student));if (p!=NULL){p->next=NULL;return p;}elsereturn NULL;
}
//*******************************************
int create(Student *p)  //输入学生信息
{int flag;Student *s;while(flag){s=(Student*)malloc(sizeof(Student));if(s==NULL){printf("创建失败\n");return 0;}printf("输入学号:");scanf("%ld",&s->num);printf("输入姓名:");scanf("%s",s->name);printf("输入C语言成绩:");scanf("%d",&s->C);printf("输入英语成绩:");scanf("%d",&s->English);printf("输入数学成绩:");scanf("%d",&s->Math);//	n=s->num;s->sum=(s->C+s->English+s->Math);s->next=p->next;p->next=s;printf("是否继续输入信息:1/0\n");scanf("%d",&flag);}printf("输入完毕\n");return 1;
}
//*******************************************
Student *Find(Student *p,int x) //查询
{Student *q;q=p->next;while(q != NULL&&q->num != x)q=q->next;if(q!=NULL)return q;elsereturn NULL;
}
//********************************************
int Modify(Student *p,int x)  //修改信息
{int flag,n;Student *q;q=p->next;while(q!=NULL&&q->num!=x)q=q->next;if(q!=NULL){while(n){printf("\n修改学科:1.C语言 2.英语 3.数学:");scanf("%d",&flag);if(flag==1){getchar();printf("\n重新输入C语言成绩:");scanf("%d",&q->C);}else if(flag==2){getchar();printf("\n重新输入英语成绩:");scanf("%d",&q->English);}else if(flag==3){getchar();printf("\n重新输入数学成绩:");scanf("%d",&q->Math);}printf("\n是否继续修改成绩:1/0\n");scanf("%d",&n);}return 1;}return 0;
}
//****************************************************
Student *Sort(Student *p)//排序
{Student *a,*b,*t;int sum=0;char name[10];if(p->next==NULL);{printf("error!!!\n");return NULL;}for(a=p->next;a;a=a->next){t=a;for(b=p->next;b;b=b->next){if(t->sum >= a->sum){strcpy(name,t->name);strcpy(t->name,a->name);strcpy(a->name,name);t=a;}}}
}
//**************************************************************
void print(Student *p)  //打印成绩
{Student *q;q = p;if(p->next == NULL)printf("无该学生成绩!");else{printf("结果为:\n");while(q->next!=NULL){q=q->next;printf("|学号\t|姓名\t|C语言\t|英语\t|高数\t|总分\t|\n");printf("|%ld\t|%s\t|%d\t|%d\t|%d\t|%d\t|\n",q->num,q->name,q->C,q->English,q->Math,q->sum);}}
}
//***************************************************************
void Menu()
{int flag,x,y;Student *p,*q,*r;x=0;p=InitStudent();	
begin:printf("\n\t\t\t   学生成绩管理系统\n");printf("1.输入学生信息   2.修改学生信息   3.查询学生信息\n");printf("4.学生成绩排序   5.打印学生信息   \n");printf("\n请输入指令前的序号:");scanf("%d",&flag);switch(flag){case 1:create(p);//print(p);goto begin;case 2:while(x==0){printf("输入学号:");scanf("%d",&x);}y=Modify(p,x);if(y==1)printf("修改成功!\n");elseprintf("修改失败!\n");x=0;goto begin;case 3:while(x==0){printf("输入学生学号:");scanf("%ld",&x);}q=Find(p,x);if(q!=NULL){printf("\n查询结果为:\n");printf("|学号\t|姓名\t|C语言\t|英语\t|高数\t|总分\t|\n");printf("|%ld\t|%s\t|%d\t|%d\t|%d\t|%d\t|\n",q->num,q->name,q->C,q->English,q->Math,q->sum);}elseprintf("未查询到!\n");x=0;goto begin;case 4:r=Sort(p);print(r);goto begin;case 5:print(p);goto begin;}
}
void main()
{Menu();
}