C programming , delete function

Question

try to use fseek to modify the name but it cannot return what result i want which is the name cannot be modify and remain the same

struct phonebook { char name[20]; };
struct phonebook a;

char temp[20];
cpPtr=fopen("name.txt","rb");//open the file
while(fread(&a,sizeof(a),1,cpPtr)==1){
    printf("Please enter name :\n");//require user to enter name
    scanf("%s",&temp);//temporary variable
    fflush(stdin);
    if(stricmp(a.name,temp)==0){
        printf("NAME :%s\n",a.name);
        else
            printf("The name is not exist");
        getch();
    }

    printf("Please enter new NAME :");
    scanf("&s",a.name);
    fflush(stdin);
    fseek(cpPtr,-sizeof(a),SEEK_CUR);//is there any wrong with seek?
    fwrite(&a,sizeof(a),1,cpPtr);
    fclose(cpPtr);
    printf("Name is modified");
    getch();
    system("cls");
}

Please read your question and see if you can understand what you are asking. I surely can't. — Neowizard, Mar 04 '13 at 07:52
i am using fseek to find my "name" in the file ,then replace the name but it cant work — BEAR, Mar 04 '13 at 08:01
using fflush(stdin); and scanf(...); [instead of fscanf(stdin);] makes my symmetric detector shiver. — Peter Miehle, Mar 04 '13 at 08:22
just my holy war: NEVER you scanf(%s) for user input. Do not even think about it. scanf has no boundary check. — Peter Miehle, Mar 04 '13 at 08:23

score 2 · Answer 1 · answered Mar 04 '13 at 08:09

2

You open the file only for reading. You have to open the file in read-write mode if you want to both read and write.

fopen("name.txt","r+b"); // open read+write

answered Mar 04 '13 at 08:09

Joni

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after i did that , I also cant modify my name , it also remain the same – BEAR Mar 04 '13 at 08:26
Add debugging statements to see what the program is doing. – Joni Mar 04 '13 at 09:04

C programming , delete function

1 Answers1