多线程并行计算数据总和 —— 优化计算思想（多线程去计算）—— C语言demo

#include <stdio.h>
#include <stdlib.h>
#include <Windows.h>
#include<process.h>
#include <time.h>
#define N 1024

struct Myinfo
{
    int *pstart;//开始地址
    int length;//长度
    int id;//线程编号
    int sum;//存储数据的和
};
void  add(void *p) //void *p可以保存任何类型的指针
{
    struct Myinfo *pinfo = p;
    for (int i = 0; i < pinfo->length;i++)
    {
        pinfo->sum += pinfo->pstart[i];
    }
    printf("n线程%d计算的结果%d", pinfo->id, pinfo->sum);
}

void main()
{
    time_t ts;
    unsigned int num = time(&ts);//传递地址
    srand(num);
    int data[N] = { 0 };
　　 // 进行赋值
    for (int i = 0; i < N; i++)
    {
        data[i] = rand() % 1000;
        //printf("%4d", data[i] = rand() % 1000);
    }
    int sum = 0;
　　 //计算总和
    for (int i = 0; i < N; i++)
    {
        sum += data[i];
    }
    printf("n总和=%d", sum);

    struct Myinfo info[8] = { 0 };
    for (int i = 0; i < 8;i++)
    {
        info[i].id = i;
        info[i].length = N / 8;
        info[i].sum = 0;
        info[i].pstart = data + i*N / 8; //注意这里地址的移动
        _beginthread(add, 0, &info[i]);
    }
    system("pause");

    int lastsum=0;
    for (int i = 0; i < 8;i++)
    {
        lastsum += info[i].sum;
    }
    printf("n多线程总和=%d", lastsum);
    system("pause");
}