第9章文件課后習題答案一、單選題1.B2.C3.C4.C5.B6.B7.D8.B9.A10.C二、程序填空題1.fopen(filename,"r")current_char=fgetc(file)lines++characters++prev_char=current_char2.fopen("source.txt","rb")fopen("destination.txt","wb")fgetc(source)putc(ch,destination)3.strlen(replace)strstr(temp,search)strcpy(output,line)line,searchStr,replaceStr,lineline,outputFile三、編程題1.#include<stdio.h>#include<stdlib.h>#include<string.h>voidfileread(charres[]);voidsaveToOther(charres[]);intmain(void){ charres[6]; fileread(res); printf("myfile文件中的內(nèi)容為："); puts(res); saveToOther(res); printf("已經(jīng)成功復制myfile中內(nèi)容至yourfile!\n"); system("pause"); return0;}voidfileread(charres[]){ FILE*fp; if((fp=fopen("myfile","rb+"))==NULL) { printf("cannotopenfilemyfile!\n"); exit(0); } else { fread(res,1,6,fp); } fclose(fp);}voidsaveToOther(charres[]){ FILE*fp; if((fp=fopen("yourfile","wb+"))==NULL) { printf("cannotopenfilemyfile!\n"); exit(0); } else { fwrite(res,1,6,fp); }}2.#include<stdio.h>#include<stdlib.h>#include<string.h>#defineSIZE20voidreadByMyfile(charres[]);voidreadByYourfile(charres[]);voidcreateOurfile(charres1[],charres2[]);voidreadByOurfile(charres[]);/*其中myfile中的內(nèi)容為Hello，yourfile中的內(nèi)容為World*/intmain(void){ charend[SIZE]; charres1[SIZE],res2[SIZE]; readByMyfile(res1); readByYourfile(res2); createOurfile(res1,res2); readByOurfile(end); printf("ourfile文件中的內(nèi)容為:\n"); puts(end); system("pause"); return0;}voidreadByMyfile(charres[]){ FILE*fp; if((fp=fopen("myfile","rb+"))==NULL) { printf("cannotopenfilemyfile!\n"); exit(0); } else { fread(res,1,6,fp);/*讀取6個1個字節(jié)長度的元素*/ } fclose(fp);/*關閉文件*/}voidreadByYourfile(charres[]){ FILE*fp; if((fp=fopen("yourfile","rb+"))==NULL) { printf("cannotopenfilemyfile!\n"); exit(0); } else { fread(res,1,6,fp);/*讀取6個1個字節(jié)長度的元素*/ } fclose(fp);/*關閉文件*/}voidcreateOurfile(charres1[],charres2[]){ FILE*fp; strcat(res1,res2);/*字符串拼接*/ if((fp=fopen("ourfile","wb+"))==NULL) { printf("cannotopenfilemyfile!\n"); exit(0); } else { fwrite(res1,1,11,fp); } fclose(fp);}voidreadByOurfile(charres[]){ FILE*fp; if((fp=fopen("ourfile","rb+"))==NULL) { printf("cannotopenfilemyfile!\n"); exit(0); } else { fread(res,1,11,fp);/*讀取6個1個字節(jié)長度的元素*/ } fclose(fp);/*關閉文件*/}3.#include<stdio.h>#include<ctype.h>#include<string.h>#defineMAX_ERRORS10//假設定錯誤類型的最大種類數(shù)#defineBUFFER_SIZE100//讀取緩沖區(qū)大小typedefstruct{charcode[5];//錯誤代碼intcount;//出現(xiàn)次數(shù)}ErrorType;intmain(){FILE*file;charbuffer[BUFFER_SIZE];Errorerrors[MAX_ERRORS]={0};intindex,found;file=fopen("log.txt","r");//日志文件路徑if(file==NULL){printf("Erroropeningfile\n");return1;}while(fgets(buffer,BUFFER_SIZE,file)){//清除前后空格buffer[strspn]=0;buffer[strtrim(buffer);//查找是否匹配錯誤類型for(index=0;index<MAX_ERRORS;index++){if(strcmp(errors[index].code,buffer)==0){errors[index].count++;break;}}//新錯誤類型if(index==MAX_ERRORS){printf("Unknownerrortype:%s\n",buffer);continue;}}fclose(file);//輸出統(tǒng)計printf("ErrorType\tCount\n");for(index=0;index<MAX_ERRORS;index++)if(errors[index].count>0)printf("%s\t%d\n",errors[index].code,errors[index].count);return0;}//輔助函數(shù)去除字符串前后空格voidstrTrim(char*str){char*end;while(isspace(*str))str++;//移動到首非空格if(*str==0)return;//空串end=str+strlen(str)-1;//尾指針while(end>str&&isspace(*end))end--;//移尾空格*(end+1)=0;//置0}4.#include<stdio.h>#include<stdlib.h>//簡單行讀取整數(shù)intreadLine(FILE*file,int*num){returnfscanf(file,"%d",num);}//寫入一行voidwriteLine(intnum,FILE*file){fprintf(file,"%d\n",num);}//快速排算法voidquickSort(intarr[],intleft,intright){inti=left,j=right,pivot=arr[(left+right)/2];while(i<=j){while(arr[i]<pivot)i++;while(arr[j]>pivot)j--;if(i<=j){inttemp=arr[i];arr[i]=arr[j];arr[j]=temp;i++;j--;}}}//主函數(shù)intmain(){FILE*inputFile,*outputFile;intarray[10000],size=0,i;inputFile=fopen("input.txt","r");outputFile=fopen("sorted.txt","w");if(inputFile==NULL||outputFile==NULL){printf("Erroropeningfiles");return1;}while(!feof(inputFile))readLine(inputFile,&array[size++]);quickSort(array,size-1);for(i=0;i<size;i++)writeLine(array[i],outputFile);fclose(inputFile);fclose(outputFile);printf("Sortingcompleted.");return0;}5./*加密*/#include<stdio.h>#defineKEY3//加密鑰，可自定義#defineBUF_SIZE100intmain(){FILE*in_file,*out_file;charbuff[BUF_SIZE],ch;in_file=fopen("original.txt","r");//原文out_file=fopen("encrypted.txt","w");//密文if(in_file==NULL||out_file==NULL){printf("Erroropeningfiles.\n");return1;}while((ch=fgetc(in_file))!=EOF){ch=ch+KEY;//加密if(ch>127)ch-=128;//ASCII超限處理fputc(ch,out_file);}fclose(in_file);fclose(out_file);prin