C语句模拟多任务实例

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

// 任务类型定义
typedef struct _myTask
{
	struct _coefficient
	{
		unsigned char a;
		unsigned char b;
		unsigned char c;
	} co;

	struct _variable
	{
		unsigned int x;
		unsigned long y;
	} v;
} myTask;

// 线程常量定义
#define THREAD_OVER			-1		// 线程结束
#define THREAD_NOTOVER		0		// 线程未结束

// 功能：任务线程
// 参数：Task:	myTask *类型，任务
//		 Process:	unsigned char * 类型，线程指针
// 返回：char 类型
//		  0: 线程未结束
//		 -1: 线程结束
// 备注：
char myThread(myTask *Task, unsigned char *Process)
{
	unsigned int z;
	char ret = 0;

	switch(*Process)
	{
		case 0:
			Task->v.x = rand();		// 获取随机数
			Task->v.y = 3;
			break;
		case 1:
			Task->v.y *= Task->v.x;
			Task->v.y *= Task->v.x;
			break;
		case 2:
			z = 7 * Task->co.a * Task->co.b * Task->v.x;
			Task->v.y += z;
			break;
		case 3:
			z = Task->co.c;
			Task->v.y += z;
	}
    printf("(*Process) = %d,\n", (*Process));
	(*Process)++;
	if(*Process>4)
	{

		ret = -1;	// 线程结束
        printf("(*Process) = %d ret = %d,\n", (*Process),ret);
		*Process = 0;
	}

	return ret;
}

// 任务定义
myTask Task1, Task2;

// 功能：任务初始化
// 参数：Task: myTask *类型，任务
//		 a, b, c：unsigned char 类型，方程式系数
// 返回：无
// 备注：
void InitTask(myTask *Task, unsigned char a, unsigned char b, unsigned char c)
{
	Task->co.a = a;
	Task->co.b = b;
	Task->co.c = c;
}

int main(void)
{
	// OS变量定义区
    // 任务1 OS变量
	char isTask_1_Living	= 1;
	unsigned char Task1_Thread_Process = 0;
	// 任务2 OS变量
	char isTask_2_Living	= 1;
	unsigned char Task2_Thread_Process = 0;

    char i=0;
	// 初始化任务
	InitTask(&Task1, 9, 7, 18);
	InitTask(&Task2, 4, 13, 16);

	for(i=0; i<5; ++i)
	{
		if(isTask_1_Living)	// 如果任务1活着
		{
			isTask_1_Living = !myThread(&Task1, &Task1_Thread_Process);
		}

		if(isTask_2_Living)	// 如果任务2活着
		{
			isTask_2_Living = !myThread(&Task2, &Task2_Thread_Process);
		}
        printf("Task1_Thread_Process = %d,\n", Task1_Thread_Process);
        printf("Task2_Thread_Process = %d,\n", Task2_Thread_Process);
	}//while

    return 0;
    //system("pause");
    //exit(0);
}

(*Process) = 0,
(*Process) = 0,
Task1_Thread_Process = 1,
Task2_Thread_Process = 1,
(*Process) = 1,
(*Process) = 1,
Task1_Thread_Process = 2,
Task2_Thread_Process = 2,
(*Process) = 2,
(*Process) = 2,
Task1_Thread_Process = 3,
Task2_Thread_Process = 3,
(*Process) = 3,
(*Process) = 3,
Task1_Thread_Process = 4,
Task2_Thread_Process = 4,
(*Process) = 4,
(*Process) = 5 ret = -1,
(*Process) = 4,
(*Process) = 5 ret = -1,
Task1_Thread_Process = 0,
Task2_Thread_Process = 0,

Terminated with return code 0
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