Thread: Need Help with Count function

Originally Posted by MSkiLLz

Sorry for the double post but I've tried editing the code trying to pass the values to the child process to find the multiple of 3 but I don't know if using the write function is the right way.

State the problem clearly; is the parent going to count the multiples of 5 and the child process count the multiples of 3? and you said that the child can't use a for loop. Correct?

Originally Posted by itCbitC

State the problem clearly; is the parent going to count the multiples of 5 and the child process count the multiples of 3? and you said that the child can't use a for loop. Correct?

Yes. The parent counts the multiples of 5 and the values that aren't multiples are passed to the child to count the multiples of 3. After that the parent displays both the count values of child and parent. The child doesn't use a for loop.

The outputs I get are "1075122321 and those of 3 are 1073836614". I was wondering if having a larger buffer would make this program work right but I noticed that you took it off. What could be making this number so large? its pretty much the same weird output I was talking about initially.

Originally Posted by itCbitC

Is that from the code posted here??

Edit: I get this output "child process: no. of multiples of 5 are 2001 and those of 3 are 3334"

Yeah. I'm using the same code. Maybe its my compiler? I'm using PuTTy.

Perhaps something got lost in the copy 'n paste. What compiler are you using? Post the code you're compiling.

Originally Posted by itCbitC

Perhaps something got lost in the copy 'n paste. What compiler are you using? Post the code you're compiling.

Code:

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

int main(void)
{
    pid_t childpid;
    int count[2];
    int fd[2];
    int m;

    pipe(fd);

    if ((childpid = fork()) == -1) {
        perror("fork");
        exit(1);
    }
    else if (childpid == 0) {
        dup2(fd[0], 0);
        read(fd[0], count, sizeof count);
        printf("child process: no. of multiples of 5 are %d"
            " and those of 3 are %d\n", count[0], count[1]);
    }
    else if (childpid > 0) {
        close(fd[0]);
        dup2(fd[1], 1);
        for (m = 0; m < 10001; m++) {
            if ((m%5) == 0)
                count[0]++;
            if ((m%3) == 0)
                count[1]++;
        }
        write(fd[1], count, sizeof count);
    }
    return 0;
}

This is the code. I'm using PuTTy.

PuTTy is not a compiler but a software for terminal emulation.

Oh. I guess I should ask you what you used and try that out.

What platform and OS are you on?

Windows Vista.

Sorry for the double post but can someone tell me why the outputs I get are extremely large for the last code posted?

What command are you issuing to compile your C program, and please learn the difference between a compiler and a terminal emulator.
*PuTTY is not a compiler*

I'm using the gcc command and executing it with ./a.out.