C language: student management system based on sequence table, super detailed, all with notes, if you don't understand it after reading, please slap me.

1. Basic function

1. add to 2. Delete 3. modify 4. lookup 5. Sort 6. Exhibition 7. sign out

2. Code implementation

2.1 The header file

#ifndef __STU_H__
#define __STU_H__
#define MAX_STU 30
typedef struct{
 char name[20];
 char sex;
 int score;
}stu_t;

typedef struct{
 stu_t stu[MAX_STU];
 int n; // Number of students in the current class 
}class_t;

#define PRINT_ERR(msg) do{\
 printf("%s",msg);\
 while(getchar()!='\n');\
 goto retry;\
}while(0)

#define ADD_STU  1
#define DEL_STU  2
#define MOD_STU  3
#define FIND_STU  4
#define SORT_STU  5
#define SHOW_STU  6
#define QUIT_STU  7

int add_stu(class_t *cls);
int delete_stu(class_t *cls);
void show_stu(class_t *cls);
int find_stu(class_t *cls);
void modify_stu(class_t *cls);
void sort_stu(class_t *cls);

#endif

2.2 Function block

#include <stdio.h>
#include <string.h>
#include "stu.h"
static int num;

void input_stu(stu_t *stu)
{
 int ret;
retry:
 printf("input (name sex score) > ");
 //scanf The return value of is the number of successful entries 
 ret = scanf("%s %c %d",
   stu->name,
   &stu->sex,
   &stu->score);
 if(ret != 3)
  PRINT_ERR("input iterm error,try again\n");

 if((stu->sex != 'm') && 
   (stu->sex != 'w'))
  PRINT_ERR("input sex  error,try again\n");

 if((stu->score < 0) || 
   (stu->score > 100))
  PRINT_ERR("input score error,try again\n");

}
int add_stu(class_t *cls)
{

 if((++cls->n) >= MAX_STU){
  printf("class full,try again\n");
  return -1;
 }

 input_stu(&cls->stu[cls->n]);

 return 0;
}
int delete_stu(class_t *cls)
{
 int i,j;
 char name[20] = {0};
 //1. Judge whether the students in the class are empty 
 if(cls->n < 0){
  printf(" There are no students in the class \n");
  return 0;
 }
 //2. Enter the name of the deleted student 
 printf("input delete stu name > ");
 scanf("%s",name);
 getchar();

 //3. To delete 
 for(i=j=0;i<=cls->n;i++){
  if(strcmp(name,cls->stu[i].name)){
   cls->stu[j] = cls->stu[i];
   j++;
  }
 }
 //4. Reset n Value 
 cls->n = j-1;

 printf(" Deleted %d A student \n",i-j);
 return i-j;
}
void print_info(stu_t *stu)
{
 printf("name = %-10s,sex = %c,score = %d\n",
   stu->name,
   stu->sex,
   stu->score);

}
void show_stu(class_t *cls)
{
 int i;
 for(i=0;i<=cls->n;i++){
  print_info(&cls->stu[i]);
 }
}

int find_stu(class_t *cls)
{
 int i,ret=0;
 char name[20] = {0};
 
 num=0;
 printf("input stu name > ");
 scanf("%s",name);
 getchar();

 for(i=0;i<=cls->n;i++){
  if(strcmp(name,cls->stu[i].name)==0){
   print_info(&cls->stu[i]);
   num = num | 1<<i;
   ret++;
  }
 }
 
 return ret;
}

void modify_stu(class_t *cls)
{
 int i,which,tmp=0,j;
 
 //1. Find students and get the number of students found 
 i = find_stu(cls);
 if(i==0){
  printf(" Failed to find students , Please check and enter \n");
  return ;
 }
 printf(" We found it %d A student \n",i);
retry:
 printf(" Please output the student information to be modified  > ");
 scanf("%d",&which);
 getchar();

 if(which <=0 || which >i){
  printf("input error,try again\n");
  goto retry;
 }
 
 for(j=0;j<=29;j++){
  if(num>>j & 0x1){
   tmp++;
   if(tmp == which) break;
  }
 }

 //2. Modify student information 
 printf(" Modifying %s Student information \n",cls->stu[j].name);
 input_stu(&cls->stu[j]);
}

void sort_stu(class_t *cls)
{
 stu_t tmp;
 int i,j;
 int flags=0;
 for(i=0;i<cls->n;i++){
  for(flags=j=0;j<cls->n-i;j++){
   if(cls->stu[j].score>cls->stu[j+1].score){
    tmp=cls->stu[j];
    cls->stu[j] = cls->stu[j+1];
    cls->stu[j+1] = tmp;
    flags=1;
   }
  }
  if(flags == 0) break;
 }
}

3main.c

#include <stdio.h>
#include <stdlib.h>
#include "stu.h"

int main(int argc, const char *argv[])
{
 int chose,loop=1;
 //1. Create a class 
 class_t *cls =(class_t *) malloc(sizeof(class_t));
 if(cls == NULL){
  printf("malloc memory error\n");
  return -1;
 }
 cls->n=-1;
 while(loop){
  puts("----------------- Welcome to student management system -----------------------");
  puts("-----1. add to  2. Delete  3. modify  4. lookup  5. Sort  6. Exhibition  7. sign out -------");
  puts("------------------------------------------------------------");
  printf("input chose > ");
  scanf("%d",&chose);
  getchar();
  
  switch(chose){
   case ADD_STU:
    add_stu(cls);
    break;
   case DEL_STU:
    delete_stu(cls);
    break;
   case MOD_STU:
    modify_stu(cls);
    break;
   case FIND_STU:
    find_stu(cls);
    break;
   case SORT_STU:
    sort_stu(cls);
    break;
   case SHOW_STU:
    show_stu(cls);
    break;
   case QUIT_STU:
    printf(" Exit the student management system \n");
    loop=0;
    break;
   default:
    printf(" Input error , Please reselect \n");
    break;
  }
 } 
 //4. Free memory 
 if(cls != NULL){
  free(cls);
  cls=NULL;
 }
 return 0;
}