Operating system Experiment--file management __ Operating system

#include <iostream> #include <ctime> #include <cstdlib> #include <vector> #include <string
> Using namespace std; #define LEN 500/************************************************** index allocation + bit table based on variable length region ******************************


/* Definition file allocation table structure */typedef struct FAT//file Allocation table file allocation tables {string filename;//filename int indexblock;//index block number}fat;
	* * Randomly generated file size/float randfilesize () {//srand (Time (seed));
float fileSize = (rand ()% bayi +)/10.0f;//randomly produces a file of 2k-10k size for return fileSize; /* * Storage File/bool Storagefile (int bittable[],vector<fat> &fat, file file, int disk[][len]) {int n = ceil (fil
	E.SIZE/2);//Up, get the number of blocks (excluding the index block) required for the file store/check if there are enough empty blocks to hold the file int i = 0;
	int k = 0;
			int index = -1;//index block for (; i < LEN; i++) {if (bittable[i) = = 0) {k++;
			if (k = = 1) {index = i;//Note the index block} if (k = = n + 1) {break;
}
		}	///There is not enough space to hold the file if (k <= N) {return false;
	}//cout << "index block:" << index <<endl; //If there are enough blank blocks to hold the file, the index block is stored on the first blank block/////////////
	Update file allocation table fat fat;
	Fat.filename = File.name;
	Fat.indexblock = index;
	
	Fat.push_back (FAT);
	Update bit table Bittable[index] = 1;
	i = index + 1;//continues to look for blank blocks from the next position in the index block k = 0;//the length int t = 0 for each segment partition;
				Locate the stored location according to the bit table, update the index block, update the bit table for (int j = 0; J < N; j +) {if (bittable[i] = 0) {if (k = = 0) {//This is a new partition, record the start block
			disk[index][t++] = i;
			} k++;
				Bittable[i] = 1;//update bit table} else{if (k!= 0) {//If k!=0 description, the partition ends, record length disk[index][t++] = k;
				cout << "\ t start block:" << disk[index][t-2] << "t length:" << disk[index][t-1] << Endl;
			DISK[INDEX][T] = -1;//set a flag k = 0;
		} j--;
	} i++;
	} disk[index][t++] = k;
	DISK[INDEX][T] =-1; cout << "\ t startBlock: "<< disk[index][t-2] <<" \ t length: "<< disk[index][t-1] << endl << Endl;
return true; int Indexblockoffile (vector<fat> Fat, String fileName) {for (int i = 0; i < fat.size (); i++) {if (fat[i).
		filename = = filename) {return fat[i].indexblock; } return-1;//Return-1 description not found}/* Delete file update bit table */bool DeleteFile (int bittable[], vector<fat> &fat, String filen
			AME, int disk[][len]) {//index block found in file allocation table for (int i = 0; i < fat.size (); i++) {if (Fat[i].filename = fileName) {
			int index = Fat[i].indexblock;
			int t = 0;
				while (Disk[index][t]!=-1) {int begin = disk[index][t];
				int len = disk[index][t + 1];
				for (int j = 0; J < Len; J +) {Bittable[begin + j] = 0;
			} T + + 2;
			} Bittable[index] = 0;
			Vector<fat>::iterator ITR = Fat.begin () +i;
			Fat.erase (ITR);
		return true;
return false; /* Output index block and stored position/void Outputindexblock (int disk[][len], vector<fat> Fat, FilE file) {string fileName = File.name;
	int size = File.size;
	cout << fileName << "T size:" << size << "K" << Endl;
			for (int i = 0; i < fat.size (); i++) {if (Fat[i].filename = = fileName) {int index = Fat[i].indexblock;
			cout << "Index block:" << index << Endl;
			int t = 0;
				while (Disk[index][t]!=-1) {int begin = disk[index][t];
				int len = disk[index][t + 1];
				cout << "\ t start block:" << begin << "T length: << len << Endl;
			T + + 2;
		} break;
	}} * * print blank block/void Outputfreeblock (int bittable[]) {cout << "free block" << Endl;
		for (int i = 0; i < LEN; i++) {if (bittable[i] = = 0) {cout << i << "\ t";
}} cout << Endl; int main () {int Bittable[len] = {0};//bit table int Disk[len][len] = {1};//disk vector<fat> Fat;//file allocation table//random Generation 2
	k-10k file 50, and store it to disk in file file[50];
	String FileName;
	float fileSize; for (int i = 0; i < i++) {fileName = to_string (i+1) + ". txt"; FileName fileSize = randfilesize ();
		Randomly generated file size file[i].name = FileName;
		File[i].size = fileSize;
		cout << fileName << "" << fileSize << "T";   Store the file if (Storagefile (bittable, FAT, file[i], disk) {//cout << "successfully created the file:" << file[i].name << "
			Size: "<< file[i].size <<" K "<< Endl; Outputindexblock (disk, FAT, file[i]);
		cout << Endl;

	}//outputfreeblock (bittable);
	cout << "\-------------------" << Endl;
		Delete odd. txt for (int i = 1; i < i + + 2) {string fileName = to_string (i) + ". txt";
		if (!deletefile (bittable, FAT, FileName, disk)) break;
	cout << "Successfully deleted file:" << fileName << Endl;
	} cout << "\ n-------------------" << Endl;
	Outputfreeblock (bittable);
	Newly created 5 files file Filea, Fileb, Filec, FileD, Filee;	Filea.name = "A.txt";
	Filea.size = 7;	Fileb.name = "B.txt";
	Fileb.size = 5; 	Filec.name = "C.txt"; Filec.siZe = 2; 	Filed.name = "D.txt";
	Filed.size = 9; 	Filee.name = "E.txt";
	Filee.size = 3.5;
	/* Storagefile (bittable, FAT, Filea, disk);
	Storagefile (bittable, FAT, Fileb, disk);
	Storagefile (bittable, FAT, Filec, disk);
	Storagefile (bittable, FAT, FileD, disk);
	Storagefile (bittable, FAT, Filee, disk); */if (Storagefile (bittable, FAT, Filea, disk) {cout << "successfully created the file:" << filea.name << Size: "<&lt ;
	Filea.size << "K" << Endl;  } if (Storagefile (bittable, FAT, Fileb, disk)) {cout << "successfully created the file:" << fileb.name << Size: "<<
	Fileb.size << "K" << Endl;  } if (Storagefile (bittable, FAT, Filec, disk)) {cout << "successfully created the file:" << filec.name << Size: "<<
	Filec.size << "K" << Endl;  } if (Storagefile (bittable, FAT, FileD, disk)) {cout << "successfully created the file:" << filed.name << Size: "<<
	Filed.size << "K" << Endl; } if (Storagefile (bittable, FAT, Filee, DISK)) {cout << "successfully created the file:" << filee.name << "size: << filee.size <<" K "<< Endl;
	} cout << "\ n-------------------" << Endl;
	Give the file allocation table of these 5 files cout << "file allocation table:" << Endl;
	/* cout << filea.name << "index block is:" << indexblockoffile (FAT, filea.name) << Endl;
	cout << fileb.name << "index block is:" << indexblockoffile (FAT, fileb.name) << Endl;
	cout << filec.name << "index block is:" << indexblockoffile (FAT, filec.name) << Endl;
	cout << filed.name << "index block is:" << indexblockoffile (FAT, filed.name) << Endl;
	cout << filee.name << "index block is:" << indexblockoffile (FAT, filee.name) << Endl; * * Outputindexblock (disk, FAT, Filea);
	cout << Endl; Outputindexblock (disk, FAT, Fileb);
	cout << Endl; Outputindexblock (disk, FAT, Filec);
	cout << Endl; Outputindexblock (disk, FAT, FileD);
	cout << Endl; OutpuTindexblock (disk, FAT, Filee);
	cout << "\-------------------" << Endl;

	Output free block Outputfreeblock (bittable);
	System ("pause");
return 0; }