26.多线程

 1 #include <Windows.h>
 2 
 3 DWORD WINAPI my_message(void *p)
 4 {
 5     MessageBoxA(0, "hello", "china", 0);
 6 
 7     return 0;
 8 }
 9 
10 void main()
11 {
12     HANDLE hthread;
13     DWORD threadid;//保存线程的编号
14 
15     for (int i = 0; i < 5; i++)
16     {
17         hthread = CreateThread(
18             NULL,//安全属性
19             NULL,//堆栈大小
20             my_message,//线程的入口点
21             NULL,//函数的参数
22             0,//立即执行
23             &threadid);//保存线程的编号
24 
25         WaitForSingleObject(hthread, INFINITE);//等待 执行完再执行下一个
26     }
27 
28     system("pause");
29 }

另一种方法实现多线程

 1 #define _CRT_SECURE_NO_WARNINGS
 2 #include <stdlib.h>
 3 #include <stdio.h>
 4 #include <process.h>
 5 #include <Windows.h>
 6 #include <string.h>
 7 
 8 //多线程函数
 9 void pro(void *p)
10 {
11     char str[100];
12     int *num = (int *)p;
13     sprintf(str, "%d", *num);
14     MessageBoxA(0, str, "多线程", 1);
15 }
16 
17 void main()
18 {
19     for (int i = 0; i < 10; i++)
20     {
21         HANDLE hd = (HANDLE)_beginthread(pro, 0, &i);
22         //WaitForSingleObject(hd,INFINITE);
23         //等待当前线程执行完再执行下一个线程
24     }
25 
26     system("pause");
27 }

多线程切割实现数值计算

 1 #define _CRT_SECURE_NO_WARNINGS
 2 #include <stdlib.h>
 3 #include <stdio.h>
 4 #include <process.h>
 5 #include <Windows.h>
 6 #include <time.h>
 7 #define N 1000
 8 
 9 //每个线程的信息
10 struct Myinfo
11 {
12     int id;//线程编号
13     int *pstart;//开始地址
14     int length;//长度
15     int sum;//存储数据的和
16 };
17 
18 //多线程函数
19 void add(void *p)
20 {
21     struct Myinfo *pinfo = (struct Myinfo *)p;
22     //根据线程信息求出相应的值
23     for (int i = 0; i < pinfo->length; i++)
24     {
25         pinfo->sum += pinfo->pstart[i];
26     }
27     printf("线程%d计算结果%d
", pinfo->id, pinfo->sum);
28 }
29 
30 
31 void main()
32 {
33     //初始化随机数种子
34     time_t ts;
35     unsigned int num = time(&ts);
36     srand(num);
37     int data[N] = { 0 };
38     //随机初始化数组
39     for (int i = 0; i < N; i++)
40     {
41         data[i] = rand() % 1000;
42     }
43 
44     
45 
46     struct Myinfo info[8] = { 0 };
47 
48     //开启八个进程
49     for (int i = 0; i < 8; i++)
50     {
51         info[i].id = i;
52         info[i].length = N / 8;
53         info[i].sum = 0;
54         info[i].pstart = data + i*N / 8;
55         _beginthread(add, 0, &info[i]);
56     }
57 
58     //求出总和
59     Sleep(1);
60     int lastsum = 0;
61     for (int i = 0; i < 8; i++)
62     {
63         lastsum += info[i].sum;
64     }
65 
66     printf("多线程总结果;%d
", lastsum);
67     system("pause");
68 }