Searching for Junk Characters in a String

Question

Friends

I want to integrate the following code into the main application code. The junk characters that come populated with the o/p string dumps the application The following code snipette doesnt work..

void stringCheck(char*);

int main()
{
    char some_str[] = "Common Application FE LBS Serverr is down";
    stringCheck(some_str);
}


void stringCheck(char * newString)
{
    for(int i=0;i<strlen(newString);i++)
    {
        if ((int)newString[i] >128)
        {

TRACE(" JUNK Characters in  Application Error message FROM DCE IS = "<<(char)newString[i]<<"++++++"<<(int)newString[i]);

        }
    }
}

Can someone please show me the better approaches to find junk characters in a string..

Many Thanks

Answer 1

Your char probably is represented signed. Cast it to unsigned char instead to avoid that it becomes a negative integer when casting to int:

if ((unsigned char)newString[i] >128)

Depending on your needs, isprint might do a better job, checking for a printable character, including space:

if (!isprint((unsigned char)newString[i])) 
    ...

Note that you have to cast to unsigned char: input for isprint requires values between 0 and UCHAR_MAX as character values.