(实验四文件管理实验.docVIP

实验四 文件管理实验 ，，为DOS系统设计一个简单的二级文件系统。要求可以实现下列几条命令 CREATE 创建文件 DELETE 删除文件 OPEN 打开文件 CLOSE 关闭文件 READ 读文件 WRITE 写文件 #define MAXNAME 25 /*the largest length of mfdname,ufdname,filename*/ #define MAXCHILD 50 /*the largest child*/ #define MAX (MAXCHILD*MAXCHILD) /*the size of fpaddrno*/ void CreateF() /*Create File*/ {int fpaddrno,flag=1,i; char fname[MAXNAME],str[50],str1[50],strtext[255],a[25]; char fmode[25]; int FindPANo(); /*find out physical address num*/ int WriteF1(); /*write file*/ int ExistF(char *filename); /*Whether FileName Exist,Exist-i,Not Exist-0*/ int ExistD(char *dirname); if (strcmp(strupr(dirname),strupr(username))!=0) {printf(\nError. You must create file in your own dir.\n);wgetchar=1;} else { printf(\nPlease input FileName:); gets(fname); ltrim(rtrim(fname)); if (ExistF(fname)=0) {printf(\nError. Name \%s\ has already existed.\n,fname); wgetchar=1; } else {printf(Please input FileMode(0-Read Only, 1-Write Only, 2-Read and Write, 3-Protect):); gets(fmode); ltrim(rtrim(fmode)); if((strcmp(fmode,0)==0)||(strcmp(fmode,1)==0)||(strcmp(fmode,2)==0)||(strcmp(fmode,3)==0)) {fpaddrno=FindPANo(); if (fpaddrno=0) {i=ExistD(username); strcpy(ufd[i]-ufdfile[fcount[i]].fname,fname); ufd[i]-ufdfile[fcount[i]].fpaddr=fpaddrno; ufd[i]-ufdfile[fcount[i]].fmode=atoi(fmode); ifopen[i][fcount[i]].ifopen=0; ifopen[i][fcount[i]].openmode=4; strcpy(str,c:\\osfile\\file\\file); itoa(fpaddrno,str1,10); strcat(str,str1); fp_file=fopen(str,wb); fclose(fp_file); fcount[i]++; while(flag) {printf(Input text now(Y/N):); gets(a); ltrim(rtrim(a)); ufd[i]-ufdfile[fcount[i]-1].flength=0; if(strcmp(strupr(a),Y)==0) {fp_file=fopen(str,wb+); ufd[i]-ufdfile[fcount[i]-1].flength=WriteF1(); flag=0; } else if(strcmp(strupr(a),N)==0){flag=0;wgetchar=1;} } printf(\n\%s\ has been created successfully!\n,fname); } else {printf(\nFail!No Disk Space.