fgets help

[mapunk]

I'm making a program that has to read in and manipulate a pgm file. I need to make sure the first line in the file is P2, not P5. How would i go about doing this?

so far i have something like this:

int continue;
FILE *in;
char buffer[MAXSIZE];

in = fopen(image.pgm, "r");

fgets(buffer, MAXSIZE, in);

if( buffer[1] != 2 )
{
    printf("Incorrect data type.\n");
    exit(0);
}

When i print out buffer[1] i get some big ass number. What am i doing wrong?

[cwr]

You want to compare the character '2', not the numeric value 2. The value '2' in ASCII for example is 50.

if (buffer[1] != '2')

Also, your filename needs to be in quotes.

[mapunk]

You want to compare the character '2', not the numeric value 2. The value '2' in ASCII for example is 50.

if (buffer[1] != '2')

Also, your filename needs to be in quotes.

ahh thanks. And i know about the file name, I actually have a variable there, but changed it just so it was easier to interpret...just forgot the quotes when i changed it

[mapunk]

second question. I'm reading a line such as this:

200 100

how would i go about setting the first number to the image height and the next to the width?

I know this isn't right....at all, I'm just having a brain fart b/c its late, and I'm posting some code for you to work with. Its something along the lines of:

            i=0;
            while(!isspace(buffer[i]))
            {
                image.width = buffer;
                i++;
                if(isspace(buffer[i]))
                {
                    break;
                }
            }

then just do the another one for the height. But how would i go about setting buffer[0] buffer[1] and buffer[2] to image.width?

[cwr]

Your input is formatted as two integers, so why don't you read it in with fgets, then use sscanf with a format specifier of "%d %d"? Check the return value of sscanf and the results for validation.