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题目.txt

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+实验二.1
+#include<stdlib.h> 
+#include<unistd.h>
+#include<stdio.h>
+
+//-------begin---------
+
+int main(){
+    pid_t son_pid,daughter_pid;
+
+    son_pid = fork();
+
+    if(son_pid<0){
+        return 1;
+    }else if(son_pid==0){
+        printf("I am son,%d,%d\n",getpid(),getppid());
+        return 0;
+    }else{
+        
+        daughter_pid = fork();
+
+        if(daughter_pid<0){
+            return 1;
+        }else if(daughter_pid==0){
+            printf("I am daughter,%d,%d\n",getpid(),getppid());
+            return 0;
+        }else{
+            printf("I am father,%d,%d,%d\n",getpid(),son_pid,daughter_pid);
+            wait(NULL);
+            wait(NULL);
+        }
+    }
+    return 0;
+}
+
+实验二.2
+#include<stdlib.h> 
+#include<unistd.h>
+#include<stdio.h>
+#include <sys/wait.h> 
+
+//-------begin---------
+
+int main(){
+    pid_t son_pid,daughter_pid;
+
+    son_pid = fork();
+
+    if(son_pid<0){
+        return 1;
+    }else if(son_pid==0){
+        printf("I am son,%d,%d\n",getpid(),getppid());
+        fflush(stdout);
+        execlp("ls", "ls", NULL);
+        exit(1);
+    }else{
+        
+        daughter_pid = fork();
+
+        if(daughter_pid<0){
+            return 1;
+        }else if(daughter_pid==0){
+            printf("I am daughter,%d,%d\n",getpid(),getppid());
+            fflush(stdout);
+            execlp("pwd", "pwd", NULL);
+            exit(1);
+        }else{
+            printf("I am father,%d,%d,%d\n",getpid(),son_pid,daughter_pid);
+            fflush(stdout);
+        }
+    }
+    return 0;
+}
+
+实验三
+#include <stdio.h>
+#include <stdlib.h>
+#include <malloc.h>
+#include <time.h>
+#define NUM 8
+#define LEN sizeof(PCB)
+struct PCB
+{
+	int name;
+	int runtime;
+    int runedtime;
+	int killtime;
+   struct PCB *next;
+};
+typedef struct PCB PCB;
+
+
+
+void main()
+{
+   int timeslice=5;
+   PCB *runqueue;
+   PCB *top,*tail,*temp;
+   int i;
+   srand((int)time(0));
+   for(i=0;i<NUM;i++)
+   { 
+     temp=(PCB*)malloc(LEN);
+     temp->name=i;
+     temp->runtime=rand()%15+1;
+     temp->runedtime=0;
+     temp->killtime=0;
+     temp->next=NULL;
+     if(i==0) 
+     {
+       top=temp; 
+       tail=temp;
+     }
+     else
+     {
+       tail->next=temp;
+       tail=temp;
+     }
+     printf("START:process name %d, runtime=%d, runedtime=%d,killtime=%d\n",tail->name,tail->runtime,tail->runedtime,tail->killtime); 
+   }
+   printf("******************************\n");
+   while(top != NULL)
+   { 
+      runqueue = top;
+      top = top->next;
+      runqueue->runtime -= timeslice;
+      runqueue->runedtime += timeslice;
+      runqueue->killtime += timeslice;
+      if(runqueue->runtime<=0)
+      {
+        free(runqueue);
+	     printf("process name %d, runtime=%d, runedtime=%d,killtime=%d...END...\n",runqueue->name,runqueue->runtime,runqueue->runedtime,runqueue->killtime);
+      }
+     else
+      {
+        tail->next = runqueue;
+        tail = runqueue;
+        tail->next = NULL;
+        printf("process name %d, runtime=%d, runedtime=%d,killtime=%d\n",runqueue->name,runqueue->runtime,runqueue->runedtime,runqueue->killtime);
+        
+     }
+   }
+}
+
+实验五
+#include <stdio.h>
+#include <stdlib.h>
+#include <malloc.h>
+#include <time.h>
+#define LEN sizeof(MEMORY_BLOCK)
+#define NUM 5
+
+struct MEMORY_BLOCK
+{
+    int name;
+    int address;
+    int length;
+    int flag;
+    struct MEMORY_BLOCK *next;
+};
+typedef struct MEMORY_BLOCK MEMORY_BLOCK;
+
+void allocation(MEMORY_BLOCK *Header, int name, int length_p);
+void reclaim(int processname, MEMORY_BLOCK *Header);
+
+void main()
+{
+    int length_p, i;
+    int processname;
+    MEMORY_BLOCK *Header, *t;
+    
+    // 初始化存储空间
+    Header = (MEMORY_BLOCK*)malloc(LEN);
+    Header->name = -1;
+    Header->address = 0;
+    Header->length = 100;
+    Header->flag = 0;
+    Header->next = NULL;
+    
+    srand((int)time(0));
+    for(i = 1; i <= NUM; i++)
+    {
+        length_p = rand() % 20 + 1;   // 随机产生进程所需存储空间，至少为1
+        allocation(Header, i, length_p);
+    }
+
+    printf("内存分配情况:  \n");
+    t = Header;
+    while(t != NULL)
+    {
+        printf("process name %d, address=%d, length=%d, flag=%d\n", 
+               t->name, t->address, t->length, t->flag);
+        t = t->next;
+    }
+
+    printf("请输入回收的进程号(输入0结束):\n");
+    scanf("%d", &processname);    
+    while(processname != 0)
+    {
+        printf("回收 process name %d\n", processname);
+        reclaim(processname, Header);
+        
+        t = Header;
+        while(t != NULL)
+        {
+            printf("process name %d, address=%d, length=%d, flag=%d\n", 
+                   t->name, t->address, t->length, t->flag);
+            t = t->next;
+        }
+        
+        if (Header->next == NULL) break;
+        
+        printf("请输入回收的进程号(输入0结束):\n");
+        scanf("%d", &processname);
+    }
+    
+    printf("当前内存分配情况：\n");
+    t = Header;
+    while(t != NULL)
+    {
+        printf("process name %d, address=%d, length=%d, flag=%d\n", 
+               t->name, t->address, t->length, t->flag);
+        t = t->next;
+    }
+}
+
+void reclaim(int processname, MEMORY_BLOCK *Header)
+{
+    MEMORY_BLOCK *temp, *t, *tt;
+    t = Header;
+    temp = t;
+    
+    // 查找要回收的进程块
+    while(t != NULL && t->name != processname)
+    {
+        temp = t;
+        t = t->next;
+    }
+    
+    if(t == NULL)
+    {
+        printf("未找到进程 %d\n", processname);
+        return;
+    }
+    
+    // 标记为空闲
+    t->name = -1;
+    t->flag = 0;
+    
+    if(t->next != NULL) // t非尾结点
+    {
+        if(temp->flag == 0 && t->next->flag == 0) // 左右都为空
+        {
+            temp->name = -1;
+            temp->length = temp->length + t->length + t->next->length;
+            tt = t->next;
+            temp->next = tt->next;
+            free(t);
+            free(tt);
+        }
+        else if(temp->flag == 0) // 左为空
+        {
+            temp->name = -1;
+            temp->length = temp->length + t->length;
+            temp->next = t->next;
+            free(t);
+        }
+        else if(t->next->flag == 0) // 右为空
+        {
+            t->length = t->length + t->next->length;
+            tt = t->next;
+            t->next = tt->next;
+            free(tt);
+        }
+        else // 左右都不为空
+        {
+            // 不需要合并，只需标记为空闲
+        }
+    }
+    else // t是尾结点
+    {
+        if(temp->flag == 0) // 左为空
+        {
+            temp->name = -1;
+            temp->length = temp->length + t->length;
+            temp->next = NULL;
+            free(t);
+        }
+        else // 左不为空
+        {
+            // 不需要合并，只需标记为空闲
+        }
+    }
+}
+
+void allocation(MEMORY_BLOCK *Header, int name, int length_p)
+{
+    MEMORY_BLOCK *temp, *t;
+    int minsize = 2; // 不可切割的分区阈值
+    
+    t = Header;
+    while(t != NULL)
+    {
+        if(t->length >= length_p && t->flag == 0) break;
+        t = t->next;
+    }
+    
+    if(t == NULL)
+    {
+        printf("无法为进程 %d 分配 %d 大小的内存\n", name, length_p);
+        return;
+    }
+    
+    if(t->length - length_p > minsize) // 分割
+    {
+        temp = (MEMORY_BLOCK*)malloc(LEN);
+        temp->name = -1;
+        temp->flag = 0;
+        temp->length = t->length - length_p;
+        temp->address = t->address + length_p;
+        
+        t->name = name;
+        t->flag = 1;
+        t->length = length_p;
+        
+        temp->next = t->next;
+        t->next = temp;
+    }
+    else  // 直接分配
+    {
+        t->name = name;
+        t->flag = 1;
+    }    
+}
+
+
+
+