C语言程序设计（第二版）第11章例题

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例11.1

#include<stdio.h>void main(){   FILE * fp;   int i=0;   char n;   fp=fopen("F:\\text.txt","r");   while(!feof(fp))   {      fscanf(fp,"%c",&n);      printf("%c",n);      i++;      if(i==10){         printf("\n");         i=0;      }   }   fclose(fp);}

例11.2

#include<stdio.h>#include<stdlib.h>void main(){    FILE * fp;    int ch;    if(!(fp=fopen("F:\\text.txt","w")))    {   printf("Cannot open file d:\\text.txt!\n");   exit(0);}ch=getchar();while(ch!=EOF){   fputc(ch,fp);   ch=getchar();}fclose(fp);return;}

例11.3

#include<stdio.h>#include<stdlib.h>void main(){    FILE * fp;    int ch;   if(!(fp=fopen("F:\\text.txt","r")))   {       printf("cannot open F:\\text.txt");       exit(0);   }   ch=fgetc(fp);;   while(ch!=EOF)   {      putchar(ch);      ch=fgetc(fp);   }   fclose(fp);   return ;  }

例11.4

#include<stdio.h>#include<stdlib.h>static void copyFile(FILE *source,FILE * intention);static FILE * openFile(char *prompt,char * mode);void main(){ FILE * source,*intention; printf("This program copies one file to another.\n"); source=openFile("source:","r"); intention=openFile("intention:","w"); copyFile(source,intention); fclose(source); fclose(intention); return ;   }static void copyFile(FILE *source,FILE * intention){   int ch;   while((ch=getc(source))!=EOF)    {   putc(ch,intention);    }}static FILE *openFile(char *prompt,char * mode){    char tmpFile[20];    FILE * reval = NULL;    while(1)    {    printf("%s",prompt);    gets(tmpFile);    reval=fopen(tmpFile,mode);    if(reval!=NULL)   break;    printf("Can't open the file \"%s\"\n",tmpFile);    exit(1);}return reval;}

例11.5

#include<stdio.h>#include<stdlib.h>void main(){   FILE *fp1;   int i,score;   if(!(fp1=fopen("f:\\text.txt","w"))){    //出错处理    printf("error");   exit(0);   }   for(i=0;i<10;i++)    //输入成绩    {        scanf("%d",&score);        fprintf(fp1,"%5d",score);   }   fclose(fp1);   return ;}

例11.6

#include<stdio.h>#include<stdlib.h>#define N 100void main(){    FILE * fp;    int i,n,s,a[N],x;    if(!(fp=fopen("F:\\text.txt","r")))    {   printf("cannot open F:\\text.txt!\n");   exit(0);}n=0;while(!feof(fp)){ fscanf(fp,"%d",&x); a[n]=x; n++;}for(s=0,i=0;i<n;i++){   s+=a[i];}printf("s=%d\n",s);fclose(fp);}

例11.7

#include<stdio.h>#include<ctype.h>#include<stdlib.h>void main(){    FILE * fp;    int n1,n2,n3,n4,ch;    n1=n2=n3=n4=0;    if((fp=fopen("F:\\text.txt","r"))==NULL)    {   printf("cannot open F:\\text.txt!\n");   exit(0);}while(!feof(fp))   {   ch=fgetc(fp);    if(isalpha(ch))        n1++;    else if(isdigit(ch))   n2++;    else if(ch==' ')            n3++;    else         n4++;   }   fclose(fp);   printf("%d %d %d %d\n",n1,n2,n3,n4);   if(fp=fopen("F:\\text.txt","a")==NULL)   {       printf("Error!\n");       exit(0);   }   fprintf(fp,"//alpha number:%d\n",n1);   fprintf(fp,"//digit number:%d\n",n2);   fprintf(fp,"//space number:%d\n",n3);   fprintf(fp,"//other:%d\n",n4);   fclose(fp);}

例11.8

#include<stdio.h>#include<stdlib.h>struct stu{   char numb[9];   int s[3];   float  ave;};void main(){   FILE * f1,* f2;   struct stu a,b;   int flag=1;   if((f1=fopen("aa.txt","r"))==NULL)   {      printf("Error!\n");      exit(0);   }   if((f2=fopen("bb.txt","w"))==NULL)   {      printf("Error!\n");      exit(0);   }   scanf("%s%d%d%d",a.numb,&a.s[0],&a.s[1],&a.s[2]);   a.ave=(a.s[1]+a.s[2]+a.s[0])/3.0;   while(fscanf(f1,"%8s%4d%4d%4d%6f\n",b.numb,&b.s[0],&b.s[1],&b.s[2],&b.ave)   !=EOF){   if(a.ave>b.ave&&flag){     fprintf(f2,"%8s%4d%4d%4d%6.1f\n",a.numb,a.s[0],a.s[1],a.s[2],a.ave);     flag = 0;   }   fprintf(f2,"%8s%4d%4d%4d%6.1f\n",b.numb,b.s[0],b.s[1],b.s[2],b.ave);      }   if(flag)     fprintf(f2,"%8s%4d%4d%4d%6.1f\n",a.numb,a.s[0],a.s[1],a.s[2],a.ave);   fclose(f1);   fclose(f2);   remove("aa.txt");   rename("bb.txt","aa.txt");}

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