如何在我的数据库中删除一个学生 [英] How Can I Delete One Student In My Database
问题描述
如何在数据库中删除一名学生？
ID姓名TC NO TEL NO ADRESS
15 A 2 5 YYY
25 B 2 6 YYY
35 C 3 7 YYY
45 D 4 8 YYY
55。
65.
当我输入id时：15 15的行必须全部删除。
我该怎么做？
How can i delete one student in my database?
ID NAME TC NO TEL NO ADRESS
15 A 2 5 YYY
25 B 2 6 YYY
35 C 3 7 YYY
45 D 4 8 YYY
55 .
65 .
WHen i enter the id : 15 15's line must be delete all above.
how can i do this ?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>
//Prototypes functions
void add_student();
void delete_student();
void modify_student();
void list_student();
//Global variables
char deleteid[12];
char updateid[12];
char data_tc_idno[12];
char data_id[13];
char data_adress[30];
char data_name[30];
char data_telno[12];
int deleteStatus[30];
int list_no;
FILE *cfPtr; //File pointer
typedef struct list{
char tc_idno[12];
char id[13];
char name[30];
char telno[13];
char adress[30];
};
struct list list2014[30];
int main(void)
{
char key_command;
printf("Student Records System v1.3 developed by Ozan Manav\n");
printf("***************************************************\n");
printf("**** | [A]Add Student with info | ****\n**** | [D]Delete Student info | ****\n**** | [U]Update Student info | ****\n**** | [L]List Students | ****\n**** | [Q]Quit | ****\n");
printf("***************************************************\n");
printf("!!! Please use ID NO for delete or update student !!!\n");
printf("***************************************************\n");
printf("Choose option: ");
do{
key_command = _getch();
if (key_command == 'a' || key_command == 'A')
add_student();
else if (key_command == 'd' || key_command == 'D')
delete_student();
else if (key_command == 'l' || key_command == 'L')
list_student();
else if (key_command == 'q' || key_command == 'Q')
exit(0);
} while (key_command != 'q' || key_command != 'Q');
system("pause");
return 0;
}
/////////////////////////////////////////////////////////////////////////////////
void add_student()
{
int n=0;
if((cfPtr = fopen("student.txt", "a+"))==NULL)
printf("FILE COULD NOT BE OPENED\n");
else{
system("cls");
printf("\n\nNumber of students enrolled:%d\n\n", list_no);
printf("This is %d.student's information.\n", list_no + 1);
printf("ID No :");
scanf("%s", list2014[list_no].id);
printf("T.C ID No:");
scanf("%s", list2014[list_no].tc_idno);
printf("Name:");
scanf("%s", list2014[list_no].name);
printf("Address :");
scanf("%s", list2014[list_no].adress);
printf("Phone Number:");
scanf("%s", list2014[list_no].telno);
system("cls");
printf("\n\n1 Student added...\n\n");
// File processing Append WRÝTE START
for(n=0;n<1;n++){
n++;
fprintf(cfPtr, "%s %s %s %s %s\n", list2014[list_no].id, list2014[list_no].tc_idno,list2014[list_no].name,list2014[list_no].adress,list2014[list_no].telno);
}
fclose(cfPtr);
// File processing END
list_no += 1;
printf("Student Records System v1.3 developed by Ozan Manav\n");
printf("***************************************************\n");
printf("**** | [A]Add Student with info | ****\n**** | [D]Delete Student info | ****\n**** | [U]Update Student info | ****\n**** | [L]List Students | ****\n**** | [Q]Quit | ****\n");
printf("***************************************************\n");
printf("!!! Please use ID NO for delete or update student !!!\n");
printf("***************************************************\n");
printf("Choose option: ");
}
}
//////////////////////////////////////////////////////////////////////////
void delete_student()
{
????????????????????????????????????
printf("\nStudent deleted...\n");
printf("\nStudent Records System v1.3 developed by Ozan Manav\n");
printf("***************************************************\n");
printf("**** | [A]Add Student with info | ****\n**** | [D]Delete Student info | ****\n**** | [U]Update Student info | ****\n**** | [L]List Students | ****\n**** | [Q]Quit | ****\n");
printf("***************************************************\n");
printf("!!! Please use ID NO for delete or update student !!!\n");
printf("***************************************************\n");
printf("Choose option: ");
}
/////////////////////////////////////////////////////////////////////////
void list_student()
{
int i;
char key_command;
system("cls");
printf("List of Students\n");
printf(" Student id------Student T.C------Student Name------Student Adress------Student Tel no\n");
if((cfPtr = fopen("student.txt", "r"))==NULL)
printf("FILE COULD NOT BE OPENED\n");
else{
fscanf( cfPtr, "%s%s%s%s%s", list2014[i].id, list2014[i].tc_idno, list2014[i].name,list2014[i].adress,list2014[i].telno);
while(!feof(cfPtr)) //kayit list_nosi degismediginden
{
printf( " %s%16s%17s%18s%20s\n", list2014[i].id, list2014[i].tc_idno, list2014[i].name,list2014[i].adress,list2014[i].telno);
fscanf( cfPtr, "%s%s%s%s%s", list2014[i].id, list2014[i].tc_idno, list2014[i].name,list2014[i].adress,list2014[i].telno);
list_no++;
}
fclose(cfPtr);
}
printf("\n");
printf("\nThere is %d student in data.\n\n", list_no);
printf("[B] Go back to the MENU\n");
printf("[Q] Quit\n");
printf("Choose option: ");
key_command = _getch();
if(key_command=='b' || key_command=='B')
{
system("cls");
printf("Student Records System v1.3 developed by Ozan Manav\n");
printf("***************************************************\n");
printf("**** | [A]Add Student with info | ****\n**** | [D]Delete Student info | ****\n**** | [U]Update Student info | ****\n**** | [L]List Students | ****\n**** | [Q]Quit | ****\n");
printf("***************************************************\n");
printf("!!! Please use ID NO for delete or update student !!!\n");
printf("***************************************************\n");
printf("Choose option: ");
}
else if (key_command == 'q' || key_command == 'Q')
exit(0);
}
/////////////////////////////////////////////////////////////////////////
i意味着我怎么能写delete_student函数请帮助......
i mean this how can i write delete_student function please help ...
推荐答案
0。初始化所有全局变量。
0. initialize all global variables.
char deleteid[12] = {0};
char updateid[12] = {0};
char data_tc_idno[12] = {0};
char data_id[13] = {0};
char data_adress[30] = {0};
char data_name[30] = {0};
char data_telno[12] = {0};
int deleteStatus[30] = {0};
struct student list2014[30] = {0};
1.重命名
1. rename your
typedef struct listto
struct student。名称列表具有误导性。对于阅读代码的人来说，像学生这样的东西应该更清楚。您将类型引用为结构，因此typedef不会为您执行任何操作。
2.加载：从文件中读取整个学生列表list2014;对于每个学生，将deleteStatus [index]设置为某个值以指示该插槽已加载且有效。在打印菜单之前调用一次。
3.打印：将完整列表打印到控制台 - 来自list2014，而不是文件。此功能应该跳过标记为已删除的学生记录（请参阅deleteStatus）或未使用。
4.删除学生，在list2014中找到学生的索引并使用该index将deleteStatus [index]设置为一个值，意思是删除。
此代码非常混乱：
. The name "list" is misleading. Something like "student" should be more clear to anyone reading your code. You reference the type as a struct, so the typedef does nothing for you.
2. load: read your whole student list "list2014" from a file; for each student, set deleteStatus[index] to some value to indicate that slot is loaded and valid. Call this once before printing menu.
3. print: print the full list to the console - from "list2014", not from a file. This function should skip student records marked as deleted (see "deleteStatus") or unused.
4. to delete a student, find the student's index in list2014 and use that index to set deleteStatus[index] to a value than means "deleted".
This code is very messy:
key_command = _getch();
if (key_command == 'a' || key_command == 'A')
add_student();
else if (key_command == 'd' || key_command == 'D')
delete_student();
else if (key_command == 'l' || key_command == 'L')
list_student();
else if (key_command == 'q' || key_command == 'Q')
exit(0);
使用toupper函数将字母转换为大写。这将简化你的if语句（甚至更好：用switch语句替换if / else）。
Use the toupper function to convert the letter to uppercase. This will simplify your if statements (even better: replace the if/else's with a switch statement).
key_command = toupper( _getch() );
if ('A' == key_command)
add_student();
else if ('D' == key_command)
delete_student();
else if ('L' == key_command)
list_student();
else if ('Q' == key_command)
exit(0);
5.保存：将完整的学生列表list2014写入另一个文件 - 在退出之前调用此方法。此功能应跳过标记为已删除的学生记录（请参阅deleteStatus）或未使用。
6.作为调试辅助工具，添加S保存命令以调用保存功能，这样你就可以看到每个操作的效果。
祝你好运。
5. save: write your full student list "list2014" to a different file - call this before exit. This function should skip student records marked as deleted (see "deleteStatus") or unused.
6. as a debugging aid, add a 'S' save command to call the save function so you can see the effects of each operation.
Good luck.
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