CODEWITHSUNDEEP
c
Master
Master

Reputation: 2153

Inserting Into Text File Blank

I ask for two simple user inputs, a user and a password, I then insert those into a text file, each followed by a semi colon. The semi colons save and the password saves but the username doesn't save for some odd reason.

For example if I input Joe with password 111222444555 it'll display as ;111222444555; instead of Joe;111222444555;

Code:

int main()
{
    int Number_Of_Attempts = 3;
    int result = 0;
    char userID[32];
    printf("Please enter your user id\n");

    scanf("%s", &userID);

    char password[12];

    printf("The user has not been found. Please enter your a password\n");


    scanf("%s", &password);


    printf("Username and Password has been saved");
    printf("\n");

    InsertIntoHash(userID, password);

    return 0;
}


void InsertIntoHash(char *userID, char *hash)
{
    FILE *fp;
    fp = fopen("HashTable.txt", "a");
    fprintf(fp, userID);
    fprintf(fp,";");
    fprintf(fp, hash);
    fprintf(fp, ";\n");
    fclose(fp);
}

Upvotes: 0

Views: 49

Answers (2)

hm1912
hm1912

Reputation: 314

You should read in the string using scanf("%31s", userID); for the userID and scanf("%11s", password); for the password.
What I think causes the problem is, that you declare and define InsertIntoHashafter the main function, without declaring a prototype at the beginning. So the code should be the following: (I tested it and it works) 

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

void InsertIntoHash(char *userID, char *hash);

int main() {
    int Number_Of_Attempts = 3;
    int result = 0;
    char userID[32];
    printf("Please enter your user id\n");
    scanf("%31s", userID);
    char password[12];
    printf("The user has not been found. Please enter your a password\n");
    scanf("%11s", password);
    printf("Username and Password has been saved");
    printf("\n");
    InsertIntoHash(userID, password);
    return 0;
}

void InsertIntoHash(char *userID, char *hash) {
    FILE *fp;
    fp = fopen("HashTable.txt", "a");
    fprintf(fp, userID);
    fprintf(fp,";");
    fprintf(fp, hash);
    fprintf(fp, ";\n");
    fclose(fp);
}

I hope I could help you! :)

Upvotes: 2

Paul Ogilvie
Paul Ogilvie

Reputation: 25286

Change scanf("%s", &userID); to scanf("%s", userID); as it is already an array which will be passed as a pointer. Same for password.

Note the buffer for password is too small: the password is 12 chars and the buffer too so the terminating null character is placed outside the buffer (resulting in Undefined Behavior, as you encounter).

Use "%11s" to limit the length read to the size of the buffer, leaving room for the terminating null character.

Upvotes: 1

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