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?
