Need help on displaying characters

[chadwickba2]

I need to be able to display every other character in my test.dat file. The test.dat file contains the number 123456.
What is the best way to go about this?


#include<stdio.h>
int main()
{
int ch;
long int offset, last;
FILE *inFile;

inFile = fopen("test.dat","r");
if (inFile == NULL)
{
printf("\nFailed to open the test.dat file. \n");
exit(1);
}
fseek(inFile,0L,SEEK_END);
last = ftell(inFile);
for(offset = 0; offset <= last ; ++offset)
{
fseek(inFile, +offset, SEEK_SET);
ch = getc(inFile);
switch(ch)
{
case '\n': printf("LF : ");
break;
case EOF : printf("EOF: ");
break;
default : printf("%c : ",ch);
}
}
fclose(inFile);

return 0;
}

[Vber]

First of all, use code tags. Second, what you want to do? print all the file? char by char?

[Brighteyes]

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    FILE *fp;
    unsigned long i;
    int c;

    fp = fopen("input.txt", "r");
    if (fp == NULL)
    {
        perror("fopen failed");
        exit(EXIT_FAILURE);
    }

    for (i = 0; (c = fgetc(fp)) != EOF; i++)
    {
        /* Skip even positions */
        if (i % 2)
            continue;

        putchar(c);
    }

    return 0;
}

[chadwickba2]

I used this part of the code and it works very well. Thanks.

	for(offset = 0; offset <= last ; ++offset)
	{
		if (offset % 2)
			continue;

[Brighteyes]

for(offset = 0; offset <= last ; ++offset)

This is very likely an off-by-one bug. By starting at 0 and going until offset is greater than last, you're actually looping last+1 times. You probably don't want to do that, so you'd have to change the loop to this

for(offset = 0; offset < last ; ++offset)

[chadwickba2]

Thank you for all the help. That line of code actually came out of the C Programming textbook that I am using. The book is not too bad, but has several mistakes in it.