C / C++ / MFC

krish_kumar wrote:

case 0 :
for (.. ; condition 1 ; ..)

krish_kumar wrote:

That's why I tried for a #define Macro. ????

#include <iostream>

int GetNextPrime(int iStartNum)
{
	int i, j;
	int i_count;
	for(i = iStartNum; ; i++) {
		for(j = 1, i_count = 0; j <= i ; j++) {
			if( (i % j) == 0 )
				++i_count;
		}
		if(i_count <= 2) {
			return i;
		}
	}
	return 0;
}

void main()
{
	int i_choice;
	int i_count;
	int i_count_1 = 0;
	int i_number = 10;
	int i, j;
	int iValNow;
	int count;

	printf("Find prime nos up to %d (press 1), or %d prime nos (press 0) ", i_number, i_number);
	scanf("%d", &i_choice);


	// ---------------------------------------------------------
	printf("\n My version: \n");
	switch(i_choice)
	{
	case 0 :	// N count.
		for(i = 0, iValNow = i, count = 0; count < i_number; i++, count++) {
			iValNow = GetNextPrime(iValNow +1);
			printf("\t %d \n", iValNow);			
		}
		break;
	case 1 :	// up to N.
		for(iValNow = 0; ; ) {
			iValNow = GetNextPrime(iValNow +1);
			if(iValNow > i_number) {
				break;
			}
			printf("\t %d \n", iValNow);
		}
		break;
	}

	// ---------------------------------------------------------
	printf("\n Your version: \n");

	switch(i_choice)
	{
	case 0 :	// N count.
		for(i = 1, i_count = 0; i_count_1 < i_number; i++ ) {
			for(j = 1,i_count = 0; j <= i ; j++) {
				if( (i % j) == 0 )
					++i_count;
			}
			if(i_count <= 2) {
				printf("\t %d \n",i);
				i_count_1++;
			}
		}
		break;

	case 1 :	// up to N.
		for(i = 1, i_count = 0 ; i <= i_number; i++ ) {
			for(j = 1, i_count = 0; j <= i ; j++) {
				if( (i % j) == 0 )
					++i_count;
			}
			if(i_count <= 2) {
				printf("\t %d \n",i);
				i_count_1++;
			}
		}
	}
}

krish_kumar wrote:

But my code is repeating twice ...I wanna avoid that....

Amir_m wrote:

Is there any way to execute XQuery through MFC Code...

class CMyAppDlg : public CDialog
{
	MSXML2::IXMLDOMDocumentPtr m_pXMLDoc;
	_RecordsetPtr m_pRs;//PRs is a ADO record set

	....
};

CString fileName(_T("C:\test.xml"));
m_pXMLDoc->load(fileName.AllocSysString());


//so I am looking for a method like
m_pRs m_pXMLDoc->ExecuteXQuery(_T("My XQuery Statement"));

SummerBulb wrote:

while (read(fd[0],buf,50) != 0)
{
printf("Read line...\n");
buf[50] = NULL;
printf(buf);
write(fileOpen, buf, 50)

CPallini wrote:

SummerBulb wrote:
while (read(fd[0],buf,50) != 0)
{
printf("Read line...\n");
buf[50] = NULL;
printf(buf);
write(fileOpen, buf, 50)



You're assuming the read function return either 0 or 50. This is a wrong assumption.

while (read(fd[0],buf,50) > 0)

CPallini wrote:

BTW Haven't you any synchronization requirement (for instance, it is ok if in the output file the content of the three input files is scrambled?)?

• read return value is -1.
• read return value is positive, but less than 50.

while ( ! finished )
{
  ssize nread = read(fd[0],buf,50);
  if ( nread == -1 )
  {
    // handle error
  }
  else if (nread > 0)
  {
    printf("Read %d characters\n", nread);
    buf[nread]='\0';
    printf(buf);
    write(fileOpen, buf, nread);
  }
}

CPallini wrote:

For instance


while ( ! finished )
{
ssize nread = read(fd[0],buf,50);
if ( nread == -1 )
{
// handle error
}
else if (nread > 0)
{
printf("Read %d characters\n", nread);
buf[nread]='\0';
printf(buf);
write(fileOpen, buf, nread);
}
}

CPallini wrote:

where finished is a termination condition (timeout?) that you possibly know better than me.

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main(int argc, char* argv[])
{
	if (argc != 5)
	{
		printf("Error!\nUsage: %s <input file 1> <input file 2> <input file 3> <output file>\n", argv[0]);
		return -1;
	}
	
	int fd[2];
	int fileOpen;
	int i;
	char buf[51];
	pipe(fd);	
	ssize_t nread;
	int count = 0;

	for (i=1; i < 4; i++)
	{
		switch (fork())
		{
		case -1:
			printf("Error: fork failure.\n");
			return -2;
		case 0:
			close(fd[0]); //child only writes to pipe
			printf("Child %d created. File: %s\n", i ,argv[i]);
			if ((fileOpen = open(argv[i], O_RDONLY)) == -1)
			{
				printf("File %s does not exist.\n", argv[i]);
				return -3;
			}
			printf("Child %d writing to pipe\n",i);
			while ((nread = read(fileOpen,buf,50)) > 0)
			{
				buf[nread] = '\0';
				printf("Child %d. Text: %s\n", i, buf);
				write(fd[1], buf, nread);
				usleep(25000*(rand()%8+3));
			}
			close(fd[1]); //child done writing
			close(fileOpen);
			printf("Child %d done writing to pipe\n",i);
			return 0;
		default:
			break;
		}
	}
	// father	
	close(fd[1]); //father only reads from pipe
	if ((fileOpen = open(argv[4],O_WRONLY|O_CREAT)) == -1)
	{
		printf("Unable to open file %s.\n", argv[4]);
		return -4;
	}
	printf("Father reading from pipe.\n");
	while (count < 1000)
	{
		if ((nread = read(fd[0],buf, 50)) > 0)
		{
			int i;
			printf("Father read line...\n");
			buf[nread] = '\0';
			printf("\n%s\n",buf);
			write(fileOpen, buf, nread);
		}
		else
		{
			printf("Father waiting for data...\n");
			usleep(10000);
		}
		count++;
	}
	close(fd[0]);
	close(fileOpen);
	printf("Father Done reading!\n");
		
	return 0;
}

SummerBulb wrote:

Here is my Code:

	int pids[3];
	int i;
//...
	for (i=1; i < 4; i++)
	{
		switch ((pids[i] = fork()))