Thread: character array filling with junk

This is a tough one for me:

A long time ago, I made myself a function that allows me to read input from user, validate it in a limited way, and put it into an array. The function:

Code:

int cInputString(int iMaxChar, char *cArr, int iValidate)
{
/* This is a character input function to limit the length of characters
   inputted by the user.  This is necessary because without using such a 
   function, user could overrun the input stack and cause errors.  It'll 
   accept single-character inputs until it hits the number of characters 
   requested (iMaxChar) or until the user hits Enter. */
/* iValidate determines whether to check for input.  Data is checked based on
   the following table:
   0: do not check data
   1: verify all data is alpha (lower and upper-case letters)
   2: verify all data is numeric */
/* int return is the length of the characters inputted */
  fflush(stdin);
  char cC;
  int iCount = 0;
  do
    {
      cC = getch();
      printf ("%c",cC);
      switch (iValidate)
      {
        case 1:
        {
          if((isalpha(cC))||cC==' '||cC==0xd)
          {
            cArr[iCount] = cC;
            ++iCount;
            break;
          }
          else
          {
            printf("\nInvalid Entry, use only letters.  Please try again: ");
            break;
          }
        }
        case 2: 
          {   
          if (atol(&cC)==0 && cC != '0' && cC != 0xd)
            {
              printf("\nInvalid Entry, use only numbers.  Please try again: ");
              break;
            }
          else if (cC == 0xd) break;
          else
            {
              cArr[iCount] = cC;
              ++iCount;
              break;
            }
          }
        default:
          {                 
            cArr[iCount] = cC;
            ++iCount;
            break;
          }
      }
    }
  while (iCount < iMaxChar && cC != 0xd);
  printf ("\n");
  fflush(stdin);
  return iCount;
}

It works perfectly to get user data:

Code:

  char cInput[7];
  cInputString(6,cInput,2);
  cInput[7]='\n';
  printf("cInput: %s",cInput);

the printf shows me exactly what I want to see. Later, I use this to build a file path:

Code:

  int k;
  char cFilename[17];
  char cPath[4] = "c:\\";
  char cAppend[5] = ".LOG";
  for(k=1;k<=31;k++)
  {
    if(k<10) snprintf(cFilename, sizeof(cFilename), "%s%s0%i%s",cPath,cInput,k,cAppend);
    else snprintf(cFilename, sizeof(cFilename), "%s%s%i%s",cPath,cInput,k,cAppend);
    printf("cInput: %s\n",cInput);
    printf("cFilename: %s\n",cFilename);
  }

The two printf statements display exactly what I want to see:
cInput: 201401
cFilename: c:\20140101.LOG

so, I open the file:

Code:

    fp=fopen(cFilename, "r+"); //FILE *fp; was earlier defined outside of the loop
    if(fp == NULL) printf("Read File Error: %s", strerror(errno));

another printf afterward to display works perfectly.

I do a bunch of reads from the file, writing to some other files, never touching cInput or cFilename again. At the end of it, before looping again with my for loop, I print it out one last time:

Code:

    printf("%s done\n\n\n",cFilename);
    printf("cInput: %s\n\n\n",cInput);
    printf("k: %i\n",k);
    printf("cAppend: %s\n",cAppend);
    system("PAUSE");

Here's what I get:

Code:

C:\20140101.LOG done


cInput: PE.ALT W33825 2014001 10 C6A ON PB04      C     @   8      E     @
    *** END OF DISPLAY ***+ @    23P043                     +


k: 1
cAppend: .LOG
Press any key to continue . . .

Any idea why that would be happening? Is there a better input (not scanf, obviously) that I could be using than the code I wrote for myself?