计算机c语言实验12.doc

实验12 文件程序设计实验目的1）掌握文件的基本概念2）掌握文本文件的打开和关闭操作3）掌握文本文件的顺序读，写方法实验内容1、基础编程题（2）将实数写入文件：从键盘输入若干实数（以特殊数值-1结束），分别写到一个文本文件中。试编写相应程序。2.1程序源代码#include int main(void) int n; FILE *pf = fopen(1.txt, w+); if (!pf) puts(open file error!); return -1; while (true) printf(input a num:); scanf(%d, &n); if (n=-1) break; fprintf(pf, %d , n); fclose(pf); puts(ok!); return 0;2.2运行结果（3）统计成绩：从键盘输入以下10个学生的学号，姓名，以及数学，语文和英语成绩，写到文本文件f3.txt中，再从文件中取出数据，计算每个学生的总成绩和平均分，并将结果显示在屏幕上。试编写相应程序。3.1程序源代码#include#include#includevoid test2();int main()test2();struct student long no; char name20; int math; int chinese; int english; int sum; double ave;void test2() struct student student_1;FILE *fp = NULL; char buff1000=学号t姓名t数学t语文t英语t总成绩t平均分; int i; fp = fopen(f3.txt, w+); fputs(buff,fp); fputs(n,fp); for(i=0;i10;i+) scanf(%ld %s %d %d %d,&student_1.no,student_1.name,&student_1.math,&student_1.chinese,&student_1.english); student_1.sum=student_1.math+student_1.chinese+student_1.english; student_1.ave=student_1.sum/3; fprintf(fp,%ldt%st%dt%dt%dt%dt%1.0lfn,student_1.no,student_1.name,student_1.math,student_1.chinese,student_1.english,student_1.sum,student_1.ave); printf(%sn,buff); fseek(fp,sizeof(buff),SEEK_SET); for(i=0;i10;i+) fscanf(fp,%ldt%st%dt%dt%dt%dt%1.0lfn,&student_1.no,student_1.name,&student_1.math,&student_1.chinese,&student_1.english,&student_1.sum,&student_1.ave); printf(%ldt%st%dt%dt%dt%dt%1.0lfn,student_1.no,student_1.name,student_1.math,student_1.chinese,student_1.english,student_1.sum,student_1.ave); fclose(fp); 3.2运行结果2、 改错题将文件中的数据求和并写入文本文件尾：文件Int_Data.dat中存放了若干整数，将文件中所有数据相加，并把累加和写入该文件的最后。2.1程序源代码#include#includeint main(void) FILE fp; int n,sum; if(fp=fopen(Int_Data.dat,r)=NULL) printf(Cant Open File!); exit(0);while(fscanf(fp,%d,&n)=EOF) sum=sum+n; fprintf(fp,%d,sum); fclose(fp); return 0;2.2运行结果2.3 实验过程将源代码改为：#include#includeint main()FILE *fp;int n,sum = 0;if(fp=fopen(int_data.dat,a+)=NULL)printf(Cant Open File!);exit(0);while(fscanf(fp,%d,&n) != EOF)sum=sum+n;fprintf(fp, %d,sum);fclose(fp);return 0;运行结果为：3、拓展编程（2）删除文件中的注释：将C语言源程序（hello.c）文件中的所有注释去掉后存入另一个文件（new_hello.c）.试编写相应程序。2.1程序源代码#include#include#includevoid test4();int main()test4();void test4()FILE *fp = NULL;FILE *fpcp = NULL;char ch; if(fp = fopen(hello.c,r)=NULL) printf(文件不存在); exit(0); ; fpcp=fopen(new_hello.c,w); while(!feof(fp) ch=fgetc(fp); if(ch=/) if(fgetc(fp)=*) while(fgetc(fp)!=/) continue; else if(ch!=EOF) fputc(ch,fpcp); fclose(fp); fclose(fpcp);2.2运行结果(3)账户余额管理：创建一个随机文件，用来存储银行账户和余额信息，程序要求能够查询某个账户的余额，当客户发生交易额时（正表示存入，负表示取出），并能更新余额。账户信息包括：账号，账号名和余额3个数据项。试编写相应程序3.1程序源代码#include #include#include long size;struct account char no10; char acctname50; double balance;FILE *openfile(char *openmode);double userbalance(FILE *fp,char *name);void pay(FILE *fp,char *name,double count);int main() FILE *fp; int choice; char name50; double balance; double count; printf(请输入选择类型n); printf(1.查账户余额n); printf(2.账户交易n); printf(退出按exitn); scanf(%d,&choice); switch(choice) case 1: printf(输入名字); scanf(%s,name); fp=openfile(r+); balance=userbalance(fp,name); printf(%.2lf,balance); break; case 2: printf(输入名字); scanf(%s,name); fp=openfile(r+); printf(输入交易金额); scanf(%lf,&count); pay(fp,name,count); break; default: exit(0); break; FILE *openfile(char *openmode) FILE *fp; if(fp=fopen(accout.dat,openmode)=NULL) printf(cant open); exit(0); return fp;double userbalance(FILE *fp,char *name) struct account user; double balance; fseek(fp,0L,SEEK_SET); while(!feof(fp) fscanf(fp,%s %s %lf,user.no,user.acctname,&user.balance); if(strcmp(user.acctname, name) = 0) balance=user.balance; break; return balance;void pay(FILE *fp,char *name,double count) FILE *fpout; struct account user; double balance; balance=userbalance(fp,name); balance=balance+count; fseek(fp,0L,SEEK_SET); fpout=fopen(temp.dat,w); while(!feof(fp) fscanf(fp,%s %s %lf,user.no,user.acctname,&user.balance); if(strcmp(user.acctname, name) = 0) user.balance=balance; /printf(%s %s %lf,user.no,user.acctname,user.balance); fprintf(fpout,%s %s %lfn,use