C++DAY29

#include "head.h"
int main(int argc, char *argv[])
{
	int fds, fdt, len, nbyte;
	pid_t pid;
	char buf[64];
	if ((fds = open("./jpg.jpg", O_RDONLY)) < 0)
	{
		perror("fail to open");
		exit(-1);
	}
 
	if ((fdt = open("./jpg1.jpg", O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
	{
		perror("fail to open");
		exit(-1);
	}
 
	len = lseek(fds, 0, SEEK_END);
	len /= 2;
 
	if ((pid = fork()) < 0)
	{
		perror("fail to fork");
		exit(-1);
	}
	else if (pid == 0)
	{
		close(fds);
		close(fdt);
		fds = open("./jpg.jpg", O_RDONLY);
		fdt = open("./jpg1.jpg", O_WRONLY);
		lseek(fds, len, SEEK_SET);
		lseek(fdt, len, SEEK_SET);
		while ((nbyte = read(fds, buf, 64)) > 0)
		{
			write(fdt, buf, nbyte);
		}
		close(fds);
		close(fdt);
	}
	else
	{
		lseek(fds, 0, SEEK_SET);
		while (len > 0)
		{
			nbyte = read(fds, buf, 64);
			write(fdt, buf, nbyte);
			len -= nbyte;
		}
		close(fds);
		close(fdt);
		wait(NULL);
	} 
	return 0;
}

C++DAY29_第1张图片 

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