Help discarding a space in char array

I have some embedded sql code that reads data from a sql database and inserts the data into a ingres isql database. That works fine. My problem lies in the code when I use atof to convert a character field (set up by outside company) in sql to a double for the ingres database. This value should have been an integer in SQL as well. So I store this char field from sql into a variable called rslt_rec_char.Hardness and if there is a space before the number (seems to be only problem) I need to remove it so the atof function will work. Can someone help me make changes to the code below to do this? Thanks. The int is_double just looks for decimal point and the function is posted below also.

Code:

---

    879        if (is_double(rslt_rec_char.Hardness))
    880            rslt_rec.Hardness = atof(rslt_rec_char.Hardness);
    881        else if (!strcmp(rslt_rec_char.Hardness,""))
    882            rslt_rec.Hardness = 0.0;
    883        else
    884        {
    885            rslt_rec.Hardness = 0.0;
    886            sprintf(jnl.mesg, "ERROR: CIN %s. Hardness test value invalid - \"%s\".\n"
    887                "Hardness in test record %s not recorded!",
    888                rslt_rec_char.CIN, rslt_rec_char.Hardness, rslt_rec_char.ResultsID);
    889            log_it(logfile,jnl);
    890            send_email(db_nm,"Met lab test upload error",jnl.mesg);
    891        }

---

Code:

---

  1421 int
  1422 is_double(char s[])
  1423 {
  1424    int index, decimal_point_found = 0;
  1425
  1426    if (!strcmp(s,"")) return 0;
  1427
  1428    for (NULL; *s && isspace(*s); s++);
  1429    if (s[0] == '-') s++;
  1430
  1431    for (index = 0; index < strlen(s); index++)
  1432    {
  1433        if (s[index] == '.') decimal_point_found++;
  1434        else if (!isdigit(s[index])) return 0;
  1435    }
  1436
  1437    return ((decimal_point_found <= 1) ? 1 : 0);
  1438 }

---

Code:

---

char * first_nonblank = rslt_rec_char.Hardness ;
while (*first_nonblank) {
  if ( isspace(*first_nonblank) ) first_nonblank++ ;
  else break ;
}

---

then use first_nonblank inside the atof() function.

Surely this:

Code:

---

    for (NULL; *s && isspace(*s); s++);

---

is much clearer as:

Code:

---

    while(*s && isspace(*s))
          s++;

---

If nothing else, you can certainly remove the NULL before the first semicolon.

Also, you isdigit doesn't allow the

Code:

---

E{,+,-}[0-9]*

---

format of floating point.

--
Mats

Thanks for pointing out some improvements for my existing code. I will look into making those changes. I plugged the code above in this morning and it works but I am seeing the space in my printf and that concerns me. I don’t think the space is being removed. I copied the code below and placed the results of the printf below the code. Any ideas why I see the output like this. Before passing the string I have to remove that space. Also I am wondering what I can do if I happen to get a string with more than one whitespace. Couldn’t that cause a memory leak with this while loop?

Code:

---

    88    char hardness[256];

    89    char *first_nonblank;

    90    double hardness2;

    91

    92    strcpy(hardness,"23.345");

    93    first_nonblank = hardness;

    94

    95    while (*first_nonblank)

    96    {

    97    if (isspace(*first_nonblank))

    98    first_nonblank++;

    99    else break;

    100    }

    101

    102    hardness2 = atof(hardness);

    103

    104    printf("%s\n", hardness);

    105     

              /* Print again this time with space*/

    106    strcpy(hardness," 23.345");

    107    first_nonblank = hardness;

    108

    109    while (*first_nonblank)

    110    {

    111    if (isspace(*first_nonblank))

    112    first_nonblank++;

    113    else break;

    114    }

    115

    116    hardness2 = atof(hardness);

    117

    118    printf("%s\n", hardness);

---

Output:

23.345

(space)23.345

Yes, you have to print the string pointed to by first_nonblank to see the space removed. It really not physically "removed", it is just not part of the new string pointed to by first_nonblank, which is what you need for atof().

Code:

---

    char hardness[256];
    char *first_nonblank;
    double hardness2;

    strcpy(hardness,"23.345");
    first_nonblank = hardness;

    while (*first_nonblank)
    {
    if (isspace(*first_nonblank))
    first_nonblank++;
    else break;
    }

    hardness2 = atof(first_nonblank);

    printf("%s\n", hardness2);

    strcpy(hardness," 23.345");
    first_nonblank = hardness;

    while (*first_nonblank)
    {
    if (isspace(*first_nonblank))
    first_nonblank++;
    else break;
    }

    hardness2 = atof(first_nonblank);

    printf("%s\n", hardness2);

---

hardness2 is a double, not a string.

The following works great thanks to Tod's help!

Code:

---

    char hardness[256];
    char *first_nonblank;
    double hardness2;

    strcpy(hardness,"23.345");
    first_nonblank = hardness;

    while (*first_nonblank)
    {
    if (isspace(*first_nonblank))
    first_nonblank++;
    else break;
    }

    hardness2 = atof(first_nonblank);

    printf("%f\n", hardness2);

    strcpy(hardness," 23.345");
    first_nonblank = hardness;

    while (*first_nonblank)
    {
    if (isspace(*first_nonblank))
    first_nonblank++;
    else break;
    }

    hardness2 = atof(first_nonblank);

    printf("%f\n", hardness2);

---

Personally, I find this:

Code:

---

while (*first_nonblank)
{
if (isspace(*first_nonblank))
first_nonblank++;
else break;
}

---

easier to read and understand as:

Code:

---

while (*first_nonblank && isspace(*first_nonblank))
{
    first_nonblank++;
}

---

Also, since the null character is not a space, you could simplify that to:

Code:

---

while (isspace(*first_nonblank))
{
    first_nonblank++;
}

---

which is even more straightforward to read and understand.

Good simplification laserlight.

Todd

I plugged your simplified version of Todds code in and it worked great! Thanks for your feedback. If there was more than one space this would work and no worrys about memory leak right?

Quote:

---

Originally Posted by cjohnman

I plugged your simplified version of Todds code in and it worked great! Thanks for your feedback. If there was more than one space this would work and no worrys about memory leak right?

---

There are no memory allocations in the code posted here, so I don't see how it could leak anything.

--
Mats

I just realized I need to discard the first space if one exists but if more than one exists do some error handling. So I only want the value if no space exists or if one exists. Other than that break out of loop and do some error handling. Any one care to help me adjust the loop laserlight posted?

Thanks in advance.

My idea would be to add an additional variable, which is originally zero, then increment it within the loop, and if it's greater than one when the loop finishes, you've got an error.

--
Mats

Actually, in that case I do not think you need a loop. If the first two characters are spaces, then there is an error. Else, if only the first character is a space, then you ignore it. Else, you can convert immediately.

I applied that to my code shown below. I need to do some tuning.. not working yet. Anything stick out as problem? The only drawback is I will have to reinitialize the variable prior to each while loop right? Any shortcuts I can take on that? Thanks again.

Code:

---

    char hardness[256];
    char *first_nonblank;
    double hardness2;
    int num_spaces = 0;

    strcpy(hardness," 23.345");
    first_nonblank = hardness;

    while (isspace(*first_nonblank))
    {
            first_nonblank++;
            num_spaces++;
    }

    if (num_spaces==0)
    {
    hardness2 = atof(first_nonblank);
    printf("%1f\n", hardness2);
    }

    else
    {
    hardness2 = 0.0;
    printf("Error:Hardness test value invalid - not recorded!");
    }

/*Next while loop I will have to remember to do num_spaces=0;*/

---

I just seen your feedback laserlight - Thanks. I will give that a shot. I will just use an if statement right?

Code:

---

    char hardness[256];
    char *first_nonblank;
    double hardness2;
    /* int num_spaces = 0; */

    strcpy(hardness," 23.345");
    first_nonblank = hardness;

    if (isspace(*first_nonblank) && isspace(*first_nonblank + 1))

        -error-

    else if (isspace(*first_nonblank) && !isspace(first_nonblank + 1))

        -convert-

    else


    hardness2 = atof(first_nonblank);
    printf("%1f\n", hardness2);

---

If you can only allow a single blank, then you could do something like this:

Code:

---

if (hardness[0]!=' ') hardness2 = atof(hardness) ;
else if (hardness[0]==' ' && hardness[1] != ' ') then hardness2 = atof(hardness+1) ;
else ...handle the error

---

As always...

Thanks Todd!!