C++DAY30

 

#include "head.h"
void* callback(void* arg)
{
	int fd, fd1, len;
	pthread_t sid;
	char c=0;
	if ((fd = open("./jpg.jpg", O_RDONLY)) < 0)
	{
		perror("fail to open");
		exit(-1);
	}
 
	if ((fd1 = open("./jpg1.jpg", O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
	{
		perror("fail to open");
		exit(-1);
	}
	len = lseek(fd, 0, SEEK_END);
	len /= 2;
	while(1)
	{
		lseek(fd,0,SEEK_SET);
		lseek(fd1,0,SEEK_SET);
		for(int i=0;i

 

#include "head.h"
char buf[]="1234567";
// A线程打印buf字符串的函数
void* printfBuf(void* arg) {
	while (1) 
	{
		// 判断buf是否等于"1234567"，如果不等于则等待条件变量发出信号
		while((strcmp(buf, "1234567") != 0)||(strcmp(buf,"7654321") != 0))
		{
			printf("%s\n", buf);//打印字符串
		}
	}
	return NULL;
}
// B线程倒置buf字符串的函数
void* circulate(void* arg) {
	while (1) 
	{
		// 判断buf是否等于"7654321"，如果不等于则等待条件变量发出信号
		while((strcmp(buf, "7654321") != 0) || (strcmp(buf,"1234567") != 0))
		{
			int len = strlen(buf);//倒置buf字符串
			for (int i = 0; i < len / 2; i++) 
			{
				char temp = buf[i];
				buf[i] = buf[len - i - 1];
				buf[len - i - 1] = temp;
			};
		}
	}
    return NULL;
}
int main(int argc, const char *argv[])
{
	pthread_t printBuf, reverseBuf;

	// 创建打印线程
	if(pthread_create(&printBuf, NULL, printfBuf, NULL) != 0)
	{
		fprintf(stderr,"printBuf failed __%d__\n",__LINE__);
		return -1;
	}
	// 创建倒置线程
	if(pthread_create(&reverseBuf, NULL, circulate, NULL) != 0)
	{
		fprintf(stderr,"reverseBuf failed __%d__\n",__LINE__);
		return -1;
	}
	// 等待线程结束
	pthread_join(printBuf, NULL);
	pthread_join(reverseBuf, NULL);
	return 0;
}