Thread: File Process Update and Delete Problem

  1. 05-18-2013 #1
    cena06
    cena06 is offline
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    File Process Update and Delete Problem

    Hi

    i have written a student information storing program.
    it has add,delete,list,and update menu
    (in program i have written update == uptade,i know : P )

    my question is i cant delete or uptade the information.
    where is my failure ?

    Code:
    #include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<conio.h>

#define max 3

struct og
{
    char id[12];
    char tc[11];
    char name[30];
    char tel[11];
    char adres[50];
}ogrenci[max],ogr[max],ex;

FILE *kp;
void menu(void);    // menu
void add(void);     // add user
void del(void);     // delete
void list(void);    // list of users
void uptade(void);  //uptade the information

void main()
{
    menu();
    system("pause");
}


void menu()
{
    char secim;
    system("cls");
    menu:
    printf("\n\n\n\t########MAIN   MENU########\n\n");
    printf("\n\t[A]-ADD NEW STUDENT\n");
    printf("\t[D]-DELETE\n");
    printf("\t[U]-UPTADE\n");
    printf("\t[L]-LIST\n");
     printf("\t[Q]-QUIT\n");
    printf("\t\n\n\n[PLEASE SELECT]\n");

    scanf("%c",&secim);
    printf("\n");
    while( getchar() != '\n' ); // gets i etkilememesi için kullandık

    switch(secim)
    {
        case 'a': add(); break;
        case 'A': add(); break;
        case 'd': del(); break;
        case 'D': del(); break;
        case 'u': uptade(); break;
        case 'U': uptade(); break;
        case 'l': list(); break;
        case 'L': list(); break;
        case 'q': exit(0); break;
        case 'Q': exit(0); break;
        default: system("cls"); goto menu; break;
    }
}

/*******************************************/
/********KAYIT FORMU***********************/

void add()
{
    
    int ret;
    int i;
    int j;
    int k;

    char temp[50];
    system("cls");
    if((kp=fopen("kayit.txt","a+"))==NULL)
    {
        printf("hata\n\n");
    } //if

    
    else
    {
        i=0;
        
        do
        {
            

        printf("enter id>\n");
        gets(temp);
        strcpy(ogrenci[i].id,temp);

        for(j=0; j<max; j++)
        {
            

            if(i==j)
            {
                continue;
            }
            

            else if(!strcmp(ogrenci[i].id,ogrenci[j].id))
            {
                printf("\nBu ID kullanilmaktadir!\n");
                printf("enter id>\n");
                gets(temp);
                strcpy(ogrenci[i].id,temp);
                break;
            }



        }// for j

        printf("\n");
        printf("enter tc no>\n");
        gets(temp);
        strcpy(ogrenci[i].tc,temp);

        for(j=0; j<max; j++)
        {
            if(j==i)
            {
                continue;
            } //if
            else if(!strcmp(ogrenci[i].tc,ogrenci[j].tc))
            {
                printf("\nBu TC NO kullanilmaktadir!\n");
                printf("enter tc no>\n");
                gets(temp);
                strcpy(ogrenci[i].tc,temp);
                break;

            } // if

        }// for j

        printf("\nenter name>\n");
        gets(temp);
        strcpy(ogrenci[i].name,temp);


        printf("\nenter tel no>\n");
        gets(temp);
        strcpy(ogrenci[i].tel,temp);


        printf("\nenter addresses>\n");
        gets(temp);
        strcpy(ogrenci[i].adres,temp);

        printf("\n");
        i++;
        }while(i<max);
        for(i=0; i<max; i++)
        {
        ret=fwrite(&ogrenci[i],sizeof(ex),1,kp);
        }
    }//else

    fclose(kp);
    menu();


}//add

void del()
{
    int i,j,ret,a;
    char id[12];

    if((kp=fopen("kayit.txt","r+"))==NULL)
    {
        printf("can not open\n");
        exit(0);
    }//if
    else
    {
        for(i=0; i<max; i++)
    {
        ret=fread(&ogrenci[i],sizeof(ex),1,kp);
    }//for
        printf("enter id for deleting>\n");
        gets(id);
        
        for(i=0; i<max; i++)
        {
        if(!strcmp(id,ogrenci[i].id))
        {
            a=i;
            break;
        }//if
        }//for

        ogrenci[a].adres[0]='\0';
        ogrenci[a].id[0]='\0';
        ogrenci[a].tc[0]='\0';
        ogrenci[a].tel[0]='\0';
        ogrenci[a].name[0]='\0';

        printf("deleted...\n");
        for(i=0; i<max; i++)
        {
        ret=fwrite(&ogrenci[i],sizeof(ex),1,kp);
        }
        fclose(kp);

    }//else

}

void uptade()
{
    
    char ch;
    char id[12];
    char tc[11];
    char name[30];
    char tel[11];
    char adres[50];
    int i,k,a;
    int ret;

    system("cls");
    
    if((kp=fopen("kayit.txt","r+"))==NULL)
    {
        printf("can not open\n");
        exit(0);
    }//if
    for(i=0; i<max; i++)
    {
        ret=fread(&ogrenci[i],sizeof(ex),1,kp);
    }//for
    printf("enter ID for updating>\n");
    gets(id);

    for(i=0; i<max; i++)
    {
        if(!strcmp(id,ogrenci[i].id))
        {
            break;
        }//if
    }//for
    select:
    printf("what do you want to update\n\n");
    printf("[i]-id\n");
    printf("[t]-tc no\n");
    printf("[n]-name\n");
    printf("[o]-tel no\n");
    printf("[a]-addresses\n");
    scanf("%c",&ch);
    printf("\n");
    while( getchar() != '\n' );
    switch(ch)
    {
    case 'i': 
        printf("enter new id>\n");
        gets(id);
        k=strlen(id);
        ogrenci[i].id[0]='\0';
        for(a=0; a<k; a++)
        {
            ogrenci[i].id[a]=id[a];
        }
        break;
    case 'I':
        
        printf("enter new id>\n");
        gets(id);
        strcpy(ogrenci[i].id,id);
        break;
    case 't':
        printf("enter new tc no>\n");
        gets(tc);
        strcpy(ogrenci[i].tc,tc);
        break;
    case 'T':
        printf("enter new tc no>\n");
        gets(tc);
        strcpy(ogrenci[i].tc,tc);
        break;
    case 'n':
        printf("enter new name>\n");
        gets(name);
        strcpy(ogr[i].name,name);
        
        break;
    case 'N':
        printf("enter new name>\n");
        gets(name);
        strcpy(ogrenci[i].name,name);
        break;
    case 'o':
        printf("enter new tel no>\n");
        gets(tel);
        strcpy(ogrenci[i].tel,tel);
        break;
    case 'O':
        printf("enter new tel no>\n");
        gets(tel);
        strcpy(ogrenci[i].tel,tel);
        break;
    case 'a':
        printf("enter new addresses>\n");
        gets(adres);
        strcpy(ogrenci[i].adres,adres);
        break;
    case 'A':
        printf("enter new addresses>\n");
        gets(adres);
        strcpy(ogrenci[i].adres,adres);
        break;
    default: printf("error\n"); goto select; break;
    }//switch
    for(i=0; i<max; i++)
    {
    ret=fwrite(&ogrenci[i],sizeof(ex),1,kp);
    }
    fclose(kp);
    printf("kaydedildi....\n");
    system("pause");
    menu();
}

void list()
{
    int i,j,ret;
    if((kp=fopen("kayit.txt","r"))==NULL)
    {
        printf("can not open\n\n");
    }//if

    for(i=0; i<max; i++)
    {
    ret=fread(&ogr[i],sizeof(ex),1,kp);
    }
    printf("\n\n-----LIST OF STUDENTS-----\n");
    for(i=0; i<max+3; i++)
    {

        printf("ID: %s\n",ogr[i].id);
        
        printf("TC NO: %s\n",ogr[i].tc);
        
        printf("NAME: %s\n",ogr[i].name);
        
        printf("TEL NO: %s\n",ogr[i].tel);
        
        printf("ADDRESSES: %s\n",ogr[i].adres);

        printf("\n");
    }//for
    fclose(kp);

    system("pause");
    menu();
    

    }
  2. 05-18-2013 #2
    Click_here
    Click_here is offline
    TEIAM - problem solved
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    void main should be int main, returning 0
    FAQ > main() / void main() / int main() / int main(void) / int main(int argc, char *argv[]) - Cprogramming.com

    You should not be using gets -> Ever
    FAQ > Why gets() is bad / Buffer Overflows - Cprogramming.com

    }//for
    This is not the correct way of making your program neat - You need to use proper indentation.
    Indent style - Wikipedia, the free encyclopedia

    The use of goto is as a loop is frowned upon in most cases. I think that a do/while loop would be more appropriate for your code.

    There is a little trick with
    Code:
    scanf("%c",&ch);

/* 
  Add a space before the %c and white characters 
  on the buffer before your input are ignored 
*/
scanf(" %c",&ch);
    When you say that you code "does not work", what is your current code doing? What do you want each section to do?
    Fact - Beethoven wrote his first symphony in C
  3. 05-18-2013 #3
    Salem
    Salem is online now
    and the hat of int overfl Salem's Avatar
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    After doing this
    ret=fread(&ogrenci[i],sizeof(ex),1,kp);

    You need to do this
    rewind(kp);

    Before doing this
    ret=fwrite(&ogrenci[i],sizeof(ex),1,kp);


    > system("pause");
    > menu();
    If you put a proper while loop in menu(), then you could just return.
    As it stands, you have potentially endless recursion.

    Code:
        case 'a':
        printf("enter new addresses>\n");
        gets(adres);
        strcpy(ogrenci[i].adres,adres);
        break;
    case 'A':
        printf("enter new addresses>\n");
        gets(adres);
        strcpy(ogrenci[i].adres,adres);
        break;
    1. NEVER use gets -> SourceForge.net: Gets - cpwiki
    2. You can shorten the code to
    Code:
        case 'a':
    case 'A':
        printf("enter new addresses>\n");
        gets(adres);
        strcpy(ogrenci[i].adres,adres);
        break;

    Code:
    #define max 3
 
struct og
{
    char id[12];
    char tc[11];
    char name[30];
    char tel[11];
    char adres[50];
}ogrenci[max],ogr[max],ex;
    1. By convention, #define names are written in uppercase, say #define MAX 3
    2. Create #defines for all the other sizes as well (#define ID_LEN 12) and so on.
    Then replace all the other magic numbers for your array sizes scattered through the code.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
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