comparing strings to pointers? Comparing strings in C

Question

So this is my code for an assignment for school, and right now my problem is in my inputID function. Where the comment says "If the same!!!!!!!!!!!!!!!!!!!!!!!!!!!", I try to compare a string given by the user and a string stored in my array of strings "IDArray". I try using the strcmp function however I keep getting an error. Any help with this would be much appreciated. The contents of the text file it reads from is shown below the code. Thank You

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_RECORDS 1000
#define MAX_INPUT 40

void writeFile();
void inputPass();
void inputID();
void userInput();
void printDB();
void readFile();
void inputInit();
void DBInit();
void init();

FILE *fp;

char **IDArray;
char **passwordArray;

char *IDInput;
char *passInput;

int main()
{
    init();
    readFile();

    printf("\n\n\tWelcome to CPS_633, Lab 1\t\n\n");

    userInput();
    writeFile();
    printDB();

    return 0;
}

void writeFile()
{
    fp = fopen("Database_Table.txt", "w");
    int i;
    for (i = 0; i < MAX_RECORDS; i++)
    {
        if (IDArray[i][0] != '\0')
        {
            fprintf(fp, "%s\t%s\n", IDArray[i], passwordArray[i]);
        }
        else
        {
            break;
        }
    }
    fclose(fp);
}

void printDB()
{
    printf("\nUsername\tPassword\n");
    int i;
    int databaseLength = 0;

    for (i = 0; i <= MAX_RECORDS; i++)
    {
        if (IDArray[i][0] != '\0')
        {
            printf("%s\t\t%s\n", IDArray[i], passwordArray[i]);
        }
        else
        {
            break;
        }
    }
}

void inputPass()
{
    int correct = 1, strLength;

    printf("Please Enter Your Password (no special characters): ");
    fgets(passInput, MAX_INPUT, stdin);
    strLength = strlen(passInput) - 1;

    if (strLength > 0 && passInput[strLength] == '\n')
    {
        passInput[strLength] = '\0';
    }

    while (correct)
    {
        int k;
        int specialCase = 1;
        for (k = 0; k <= strLength; k++) //Searches for special characters
        {
            switch (passInput[k])
            {
            case '~':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '!':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '`':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '@':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '#':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '$':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '%':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '^':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '&':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '*':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '(':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case ')':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '-':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '_':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '=':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '+':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '[':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case ']':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '{':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '}':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '|':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '\\':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case ':':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case ';':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;

            case '"':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case ',':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '<':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '.':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '>':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '?':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            case '/':
                printf("Special Character(s) Found\n");
                specialCase = 0;
                break;
            }
            if (specialCase == 0)
                break;
        }
        if (specialCase != 0)
        {
            if (strLength > 12) //Password longer than 12 characters
            {
                printf("This password is too long, the characters after the 12th has been cut off\n");
                int i;
                for (i = 0; i < MAX_RECORDS; i++)
                {
                    if (passwordArray[i][0] == '\0')
                    {
                        strncpy(passwordArray[i], passInput, 12);
                        break;
                    }
                    else
                    {
                        continue;
                    }
                }
                correct = 0;
            }
            else //Password shorter than 12 characters
            {
                int i, j;
                for (j = strLength; j <= 12; j++) //Pads password with "-"
                {
                    passInput[j] = '-';
                }

                for (i = 0; i < MAX_RECORDS; i++) // Traverses array for first empty slot
                {
                    if (passwordArray[i][0] == '\0') //If empty insert
                    {
                        strncpy(passwordArray[i], passInput, 12);
                        break;
                    }
                    else // If not empty continue
                    {
                        continue;
                    }
                }
                correct = 0;
            }
        }
        else
        {
            printf("Please Enter Your Password (no special characters): ");
            fgets(passInput, MAX_INPUT, stdin);
            strLength = strlen(passInput) - 1;

            if (strLength > 0 && passInput[strLength] == '\n')
            {
                passInput[strLength] = '\0';
            }
        }
    }
}

void inputID()
{
    int correct = 1, strLength;

    printf("Please Enter Your Username ID: ");
    fgets(IDInput, MAX_INPUT, stdin);
    strLength = strlen(IDInput) - 1;

    if (strLength > 0 && IDInput[strLength] == '\n')
        IDInput[strLength] = '\0';

    while (correct)
    {
        if (strLength > 32) //If longer than 32 characters
        {
            printf("This Username ID is longer than 32 characters\n");
            printf("Please Enter Your Username ID: ");
            fgets(IDInput, MAX_INPUT, stdin);

            strLength = strlen(IDInput) - 1;

            if (strLength > 0 && IDInput[strLength] == '\n')
                IDInput[strLength] = '\0';
        }
        else if (strLength < 4) //If shorter than 4 characters
        {
            printf("This Username ID is shorter than 4 characters\n");
            printf("Please Enter Your Username ID: ");
            fgets(IDInput, MAX_INPUT, stdin);

            strLength = strlen(IDInput) - 1;

            if (strLength > 0 && IDInput[strLength] == '\n')
                IDInput[strLength] = '\0';
        }
        else //If acceptable length
        {
            int i;
            for (i = 0; i < MAX_RECORDS; i++) 
            {
                if (IDArray[i][0] != '\0') //If element occupied, compare
                {
                    if (strcmp(IDArray[i], inputID) == 0) // If the same!!!!!!!!!!!!!!!!!!
                    {
                        printf("Found Match");
                        correct = 0;
                        break;
                    }
                    else //If not the same
                    {
                        continue;
                    }
                }
                else //If element empty, insert
                {
                    strcpy(IDArray[i], IDInput);
                    break;
                }
            }
            correct = 0;
        }
    }
}

void userInput()
{
    inputID();
    inputPass();
}

void readFile()
{
    fp = fopen("Database_Table.txt", "r");

    char line[MAX_INPUT];
    if (fp == NULL)
    {
        perror("Error in opening file");
    }
    else
    {
        int i = 0;
        while (!feof(fp))
        {
            if (fgets(line, sizeof(line), fp) == NULL)
            {
                break;
            }
            else
            {
                sscanf(line, "%s\t%s", IDInput, passInput);
                strcpy(IDArray[i], IDInput);
                strcpy(passwordArray[i], passInput);
                i++;
            }
        }
    }
    fclose(fp);
}

void inputInit()
{
    IDInput = (char *)malloc(sizeof(char) * MAX_INPUT);
    passInput = (char *)malloc(sizeof(char) * MAX_INPUT);
}

void DBInit()
{
    IDArray = (char **)malloc(sizeof(char *) * MAX_RECORDS);
    passwordArray = (char **)malloc(sizeof(char *) * MAX_RECORDS);

    int i, j;
    for (i = 0; i < MAX_RECORDS; i++)
    {
        IDArray[i] = (char *)malloc(sizeof(char) * MAX_INPUT);
        passwordArray[i] = (char *)malloc(sizeof(char) * MAX_INPUT);
        for (j = 0; j < MAX_INPUT; j++)
        {
            IDArray[i][j] = '\0';
            passwordArray[i][j] = '\0';
        }
    }
}

void init()
{
    DBInit();
    inputInit();
}

ID11 PASSWORD1

ID22 PASSWORD2

ID33 PASSWORD3

ID44 PASSWORD4

ID55 PASSWORD5

Nuke and rebuild. NEVER NEVER store passwords in plaintext for verification. It's an assignment you say. Complain the assignment teaches really bad habits. — Joshua, Oct 02 '16 at 23:49
No, I understand that it's bad habit to do that. I haven't applied the hashing function yet. This is for a security class loll — Andy Steven Llactahuamani, Oct 02 '16 at 23:50
Please try and create an MVCE (http://stackoverflow.com/help/mcve). Also, whenever you want to know why something is causing an error, you need to give the full error message... — Ben Wainwright, Oct 02 '16 at 23:57
Doesn't the 30 repeats of almost the same code in `inputPass()` make you cry? It does me. What about control characters (tabs, etc)? Have you come across `` and functions/macros like `ispunct()`? It's doubly bad when you force us to look at 120 lines of code when half a dozen would do the job — that's 20 times as much code as necessary to read and ignore (hoping that the problem isn't an inconsistency in that block of code!). Even if you listed 30 cases and 3 lines of code after them, it would be 33 lines vs 120). Please read about how to create an MCVE ([MCVE]), as already requested. — Jonathan Leffler, Oct 03 '16 at 01:34
Also, the actual problem, correctly diagnosed by [deamentiaemundi](http://stackoverflow.com/users/4241278/deamentiaemundi), is that you're comparing a function pointer with a string. The compiler should be shrieking at you 'incompatible types'. If it is, don't forget to mention it; that's your problem. At this stage in your career as a C programmer, the compiler doesn't make mistakes and if it gives you a warning, it needs to be fixed. It will be a while before you can afford to ignore warnings — I seldom ignore any, but I've only been coding C for 30 years so there's lots left to learn. — Jonathan Leffler, Oct 03 '16 at 01:37
Oh, and if the compiler isn't shrieking at you about your mistake, you either need to turn on more warnings or you need to get a better compiler. The code should not be compiling without at least warnings. Were I to try compiling it under my default compilation flags, it would fail on that (and a number of other issues of greater or lesser significance). — Jonathan Leffler, Oct 03 '16 at 01:40

score 0 · Answer 1 · answered Oct 03 '16 at 00:06

0

You have a typo in line 325 (the line with that comment): it's IDInput you want to compare with, not inputID which is the name of the function it's in.

answered Oct 03 '16 at 00:06

deamentiaemundi

5,502
2
12
20

OMG thanks for that, I hate when it's the stupidest things that messes up your code. – Andy Steven Llactahuamani Oct 03 '16 at 00:22
@AndyStevenLlactahuamani yes, that happens. More interesting is to know who does not want me to tell you that? ;-) – deamentiaemundi Oct 03 '16 at 00:23

comparing strings to pointers? Comparing strings in C

1 Answers1