操作系统实验—动态分区分配算法

}

void print2() //打印作业分区 {

int i;

for (i = 0; i

printf(\作业分区ID：%d 起止:%d 结束:%d 长度:%d\\n\, i, zuoye[i].start, zuoye[i].end, zuoye[i].length); }

int main() {

int i, j, t, len, flag, id; int front, middle, behind; int t1, t2; init(); print1();

printf(\输入1装入新作业，输入0回收作业，输入-1结束\\n\); while (scanf(\, &t) != EOF) {

if (t == 1) //装入新作业 {

printf(\请输入作业的占用空间的长度 \); scanf(\, &len); flag = 0;

for (i = 0; i

if (kongxian[i].length >= len) //首次适应算法 {

flag = 1; break; } }

if (!flag) {

printf(\内存分配失败\\n\); } else {

//将该作业加入作业区里

zuoye[n2].start = kongxian[i].start; zuoye[n2].end = zuoye[n2].start + len; zuoye[n2].length = len; n2++; //作业数加1

if (kongxian[i].length == len) //该分区全部用于分配，删除该空闲分区

{

for (j = i; j

kongxian[j].start = kongxian[j + 1].start; kongxian[j].end = kongxian[j + 1].end;

kongxian[j].length = kongxian[j + 1].length; } n1--; }

else//该空闲分区部分用于分配，剩余的留在空闲分区中 {

kongxian[i].start += len; kongxian[i].length -= len; } } }

elseif (t == 0) {

printf(\输入要回收的作业ID \); scanf(\, &id);

front = middle = behind = 0; for (i = 0; i

if (kongxian[i].start>zuoye[id].end) break;

if (kongxian[i].end == zuoye[id].start) //待回收的作业上面有空闲分区 {

front = 1; t1 = i; }

if (kongxian[i].start == zuoye[id].end) //待回收的作业下面有空闲分区 {

behind = 1; t2 = i; } }

if (!front&&!behind) //待回收的作业上下均没有空闲分区 {

kongxian[n1].start = zuoye[id].start; kongxian[n1].end = zuoye[id].end;

kongxian[n1].length = zuoye[id].length; n1++; //空闲分区增加一个

qsort(kongxian, n1, sizeof(structkongxian), cmp1); //插入空闲分区后排序

for (j = id; j

zuoye[j].start = zuoye[j + 1].start; zuoye[j].end = zuoye[j + 1].end;

zuoye[j].length = zuoye[j + 1].length; }

n2--; }

if (front &&behind) //待回收的作业上下均有空闲分区 middle = 1;

if (front&&!middle) //合并待回收的作业和上面的空闲分区 {

kongxian[t1].end += zuoye[id].length; kongxian[t1].length += zuoye[id].length;

for (j = id; j

zuoye[j].start = zuoye[j + 1].start; zuoye[j].end = zuoye[j + 1].end;

zuoye[j].length = zuoye[j + 1].length; }

n2--; }

if (middle) //合并待回收的作业和上下的空闲分区 {

kongxian[t1].end = kongxian[t2].end;

kongxian[t1].length +=(zuoye[id].length + kongxian[t2].length);

//删除空闲分区t2

for (j = t2; j

kongxian[j].start = kongxian[j + 1].start; kongxian[j].end = kongxian[j + 1].end;

kongxian[j].length = kongxian[j + 1].length; }

n1--;

for (j = id; j

zuoye[j].start = zuoye[j + 1].start; zuoye[j].end = zuoye[j + 1].end;

zuoye[j].length = zuoye[j + 1].length; }

n2--;

}

}

if (behind &&!middle) //合并待回收的作业和下面的分区 {

kongxian[t2].start -= zuoye[id].length; kongxian[t2].length += zuoye[id].length;

for (j = id; j

zuoye[j].start = zuoye[j + 1].start; zuoye[j].end = zuoye[j + 1].end;

zuoye[j].length = zuoye[j + 1].length; }

n2--; } } else {

printf(\操作结束\\n\); break; }

print1(); print2(); }

return 0;

3.程序运行时的初值和运行结果。

初始：

装入实验要求作业一：