我tryimg寫一個C程序,將搜索另一個給定的整數的整數數組。但是,爲了加速搜索,搜索由兩個子進程並行完成。父進程讀入整數的數量,然後讀入數組中的整數。它還讀入要搜索的整數。然後它創建兩個子進程。第一個子進程搜索數組的前半部分,第二個子進程搜索後半部分。如果找到整數,則其數組中的索引通過管道發送到父級。如果找不到,則通過管道將-1發送給父級。父級等待兩個子進程完成,然後打印一條適當的消息。通過管道親子進程通信
我已經諮詢了一些書,這就是我想出的。雖然有一個小問題...兩個子進程依次運行,而不是並行運行。我應該做什麼改變?
#include<stdlib.h>
#include<stdio.h>
#include<unistd.h>
#include<sys/ipc.h>
#include <string.h>
void main()
{
int i,status,num1,num2,num3,num4, fd1[2], fd2[2];
int a[1000];
char b[5],c[5],d[5],e[5];
pid_t pid1,pid2;
printf("\n\n\nEnter how many numbers - ");
scanf("%d",&num1);
//printf("\n\nEnter the %d numbers below -\n",num1);
for (i=0;i<num1;i++)
{
printf("%d : ",i);
scanf("%d",&a[i]);
}
printf("\n\nEnter the number to search - ");
scanf("%d",&num2);
pipe(fd1);
pipe(fd2);
pid1=fork();
if (pid1==0)
{
printf("this is the child 1\n");
for (i=0;i<(num1/2);i++)
{
if (a[i]==num2)
{
printf("found by process 1\n");
sprintf(b,"%d",i);
sprintf(c,"%d",-1);
write(fd1[1],&b,4);
write(fd2[1],&c,4);
//kill(0,1);
break;
}
printf("%d\n",a[i]);
}
_exit (EXIT_FAILURE) ;
}
else
if (pid1>0)
{
pid2=fork();
if (pid2==0)
{
printf("this is the child 2\n");
for (i=(num1/2);i<num1;i++)
{
if (a[i]==num2)
{
printf("found by process 2\n");
sprintf(b,"%d",-1);
sprintf(c,"%d",i);
write(fd1[1],&b,4);
write(fd2[1],&c,4);
//kill(0,1);
break;
}
printf("%d\n",a[i]);
}
_exit(EXIT_FAILURE);
}
}
if (waitpid (pid1, &status, 0)>0 && waitpid (pid2, &status, 0)>0)
{
read(fd1[0],d,4);
read(fd2[0],e,4);
num3=atoi(d);
num4=atoi(e);
if (num3>0) printf("value of i is %d\n",num3);
if (num4>0) printf("value of i is %d\n",num4);
}
}
改爲使用線程(https://computing.llnl.gov/tutorials/pthreads/):您不必處理進程間問題,而且需要的資源更少(創建新進程比創建線)。 – ern0
@ ern0我試過,但我的教授希望這樣做:-( – rits