Search in binary mode

[hyoutereda]

This program's purpose is to find the location of "AA BB CC 23 7F"(5 bytes) in a binary file.
A file(argv[1]) is sure to have "AA BB CC 23 7F".
However, this program sometimes don't work.
Why?
Then, please teach me better codes.

====== code (a part) ==========================

int main(int argc, char *argv[])
{

FILE *fptr1;
int b_index;
int b[5];
int lb1[5] = {0xAA, 0xBB, 0xCC, 0x23, 0x7F};
long point1;

fptr1 = fopen(argv[1], "rb");

fseek(fptr1, 0L, SEEK_SET);
for(b_index = 0; b_index < 5; b_index++)
b[b_index] = getc(fptr1);

do{
for(b_index = 0; b_index < 4; b_index++)
b[b_index] = b[b_index + 1];
b[4] = getc(fptr1)
}while(b[0] != lb1[0] || b[1] != lb1[1] || b[2] != lb1[2]
|| b[3] != lb1[3] || b[4] != lb1[4]);

point1 = ftell(fptr1);
printf("point1 = %X/n", point1);

}

=============================================

[Monster]

Here some help:
[list=1][*]Always check the number of arguments before you use them:

if(argc != 2)
{
    printf("Usage: %s <filename>\n", argv[0]);
    return -1;
}

[*]Always check return values:

if((fptr1 = fopen(argv[1], "rb")) == NULL)
{
    printf("Could not open file: %s\n", argv[1]);
    return -2;
}

[*]Check the return value of the getc function for EOF:

if((b[4] = getc(fptr1)) == EOF)
{
    printf("Parrern not found\n");
    return -3;
}

[*]Return something (0) at the end of main.
[*]Use code tags[/list=1]

Cheers,
Monster