Modulization Gone Awry - c

Question

So I had one large function that worked. Then I decided to modify it and now I am just printing out a black square. I am attaching my code to see if any one would understand what is happening. These three function where once large function:
Function 1
int
readpgm (pgm_type * header, char input[80], char output[80])
{
FILE *instream;
int size, read;
instream = fopen (input, "rb");
fileChecker (instream);
fscanf (instream, "%2s%d%d%d", header->filetype, &header->width,
&header->height, &header->maxgray);
if (!header->filetype[0] == 'P' || !header->filetype[1] == '5') {
fatal ("Incorrect Type");
}
size = header->width * header->height;
header->p = malloc (size * sizeof (char));
read = fread (header->p, 1, size, instream);
if (read != size) {
fatal ("Incorrect Size");
}
return size;
}
void
crop (pgm_type * header, char output[80])
{
printf ("Height: %i, Width: %i, Total pixels: %i \n", header->height,
header->width, header->height * header->width);
int temp, y1, y2, x1, x2, wide, high;
printf ("Please Enter x1 y1 x2 y2 \n");
scanf ("%i %i %i %i", &x1, &y1, &x2, &y2);
if (y1 > y2) {
temp = y1;
y1 = y2;
y2 = temp;
}
if (x1 > x2) {
temp = x1;
x1 = x2;
x2 = temp;
}
wide = x2 - x1 + 1;
high = y2 - y1 + 1;
printFile (wide, high, x1, x2, y1, y1, header, output);
}
void
printFile (int wide, int high, int x1, int x2, int y1, int y2,
pgm_type * header, char output[80])
{
FILE *outstream;
outstream = fopen (output, "wb");
fileChecker (outstream);
fprintf (outstream, "%2s\n%i %i\n%i\n", header->filetype, wide, high,
header->maxgray);
pixel image[header->height][header->width];
pixel *pix = malloc ((wide * high) * sizeof (char));
int a = 0;
for (int b = 0; b < header->height; ++b) {
for (int c = 0; c < header->width; ++c) {
image[b][c] = header->p[a];
++a;
}
}
int k = 0;
for (int i = y1; i <= y2; ++i) {
for (int j = x1; j <= x2; ++j) {
pix[k] = image[i][j];
++k;
}
}
fwrite (pix, 1, (wide * high) * sizeof (pixel), outstream);
free (pix);
fclose (outstream);
}
The first two function are call in main.

Answer 1

This works for me.
//gcc c2.c -std=c99 -g -Wall -Wextra
#include <stdio.h>
#include <malloc.h>
#include <assert.h>
typedef struct pgm_type pgm_type;
struct pgm_type{
char filetype[2];
int width,height,maxgray;
unsigned char*p;
};
int
readpgm (pgm_type * header, char*fn)
{
FILE *instream;
int size, read;
instream = fopen (fn,"rb");
assert(instream);
fscanf (instream, "%2s%d%d%d", header->filetype, &header->width,
&header->height, &header->maxgray);
printf("%2s %d %d %d\n",header->filetype,header->width,
header->height,header->maxgray);
if (!header->filetype[0] == 'P' || !header->filetype[1] == '5') {
printf ("Incorrect Type");
}
size = header->width * header->height;
header->p = malloc (size * sizeof (char));
read = fread (header->p, 1, size, instream);
if (read != size) {
printf ("Incorrect Size");
}
return size;
}
void
printFile (int x1, int x2, int y1, int y2,pgm_type * header, char*fn)
{
FILE *outstream;
int wide=x2-x1+1,high=y2-y1+1;
printf("cropping to %dx%d\n",wide,high);
outstream = fopen (fn, "wb");
assert (outstream);
fprintf (outstream, "%2s\n%i %i\n%i\n", header->filetype, wide, high,
header->maxgray);
unsigned char image[header->height][header->width];
unsigned char *pix = malloc ((wide * high) * sizeof (char));
int a = 0;
for (int b = 0; b < header->height; ++b) {
for (int c = 0; c < header->width; ++c) {
image[b][c] = header->p[a];
++a;
}
}
int k = 0;
for (int j = y1; j <= y2; ++j) {
for (int i = x1; i <= x2; ++i) {
pix[k] = image[j][i];
++k;
}
}
fwrite (pix, wide,high, outstream);
free (pix);
fclose (outstream);
}
int
main()
{
pgm_type h;
readpgm(&h,"lena.pgm");
printFile(64,129,32,230,&h,"o2.pgm");
return 0;
}