C语言文件操作概述

FILE *fopen(char *pname,char *mode)

//定义一个名叫fp文件指针
FILE *fp；
//判断按读方式打开一个名叫test的文件是否失败
if((fp=fopen（"test"，"r"）) == NULL)//打开操作不成功
{ printf("The file can not be opened.\n")； exit(1);//结束程序的执行
}

int fclose(FILE *fp)；

int n=fclose(fp);

int fgetc(FILE *fp)；

//程序名为：display.c
//执行时可用：display filename1 形式的命令行运行。显示文件filename1中的内容。例如，执行命令行display display.c将在屏幕上显示display的原代码。

//File display program.
#include <stdio.h>
void main(int argc,char *argv[]) //命令行参数
{ int ch;//定义文件类型指针
 FILE *fp;//判断命令行是否正确
 if(argc!=2) { printf("Error format,Usage: display filename1\n"); return; //键入了错误的命令行，结束程序的执行
 } //按读方式打开由argv[1]指出的文件
 if((fp=fopen(argv[1],"r"))==NULL) { printf("The file <%s> can not be opened.\n",argv[1]);//打开操作不成功
 return;//结束程序的执行
 } //成功打开了argv[1]所指文件
 ch=fgetc(fp); //从fp所指文件的当前指针位置读取一个字符
 while(ch!=EOF) //判断刚读取的字符是否是文件结束符
 { putchar(ch); //若不是结束符，将它输出到屏幕上显示
 ch=fgetc(fp); //继续从fp所指文件中读取下一个字符
 } //完成将fp所指文件的内容输出到屏幕上显示
 fclose(fp); //关闭fp所指文件
}

int fputc(int ch,FILE *fp)

//程序名为：copyfile.c
//执行时可用：copyfile filename1 filename2形式的命令行运行，将文件filename1中的内容复制到文件filename2中去。
//file copy program.
#include <stdio.h>
void main(int argc,char *argv[]) //命令行参数
{ int ch; FILE *in,*out; //定义in和out两个文件类型指针
 if(argc!=3) //判断命令行是否正确
 { printf("Error in format,Usage: copyfile filename1 filename2\n"); return; //命令行错，结束程序的执行
 } //按读方式打开由argv[1]指出的文件
 if((in=fopen(argv[1],"r"))==NULL) { printf("The file <%s> can not be opened.\n",argv[1]); return; //打开失败，结束程序的执行
 } //成功打开了argv[1]所指文件，再
 //按写方式打开由argv[2]指出的文件
 if((out=fopen(argv[2],"w"))==NULL) { printf("The file %s can not be opened.\n",argv[2]); return; //打开失败，结束程序的执行
 } //成功打开了argv[2]所指文件
 ch=fgetc(in); //从in所指文件的当前指针位置读取一个字符
 while(ch!=EOF) //判断刚读取的字符是否是文件结束符
 { fputc(ch,out); //若不是结束符，将它写入out所指文件
 ch=fgetc(in); //继续从in所指文件中读取下一个字符
 } //完成将in所指文件的内容写入（复制）到out所指文件中
 fclose(in); //关闭in所指文件
 fclose(out); //关闭out所指文件
}

//程序名为：dumpf.c
//执行时可用：dumpf filename1 形式的命令行运行。
// File dump program.
#include <stdio.h>
void main(int argc,char *argv[])
{ char str[9]; int ch,count,i; FILE *fp; if(argc!=2) { printf("Error format,Usage: dumpf filename\n"); return; } if((fp=fopen(argv[1],"r"))==NULL) { printf("The file %s can not be opened.\n",argv[1]); return; } count=0; do{ i=0; //按八进制输出第一列，作为一行八个字节的首地址
 printf("%06o: ",count*8); do{ // 从打开的文件中读取一个字符
 ch=fgetc(fp); // 按十进制方式输出这个字符的ASCII码
 printf("%4d",ch); // 如果是不可示字符就用"#"字符代替
 if(ch<' '||ch>'~') str[i]='#'; // 如果是可示字符，就将它存入数组str以便形成字符串
 else str[i]=ch; // 保证每一行输出八个字符
 if(++i==8) break; }while(ch!=EOF); // 遇到文件尾标志，结束读文件操作
 str[i]='\0'; // 在数组str加字符串结束标志
 for(;i<8;i++) printf(" "); // 一行不足八个字符用空格填充
 printf(" %s\n",str); // 输出字符串
 count++; // 准备输出下一行
 }while(ch!=EOF); // 直到文件结束
 fclose(fp); // 关闭fp所指文件
}

char *fgets(char *str,int n,FILE *fp)

int fputs(char *str,FILE *fp)

//程序名：linkfile.c
//执行时可用：linkfile filename1 filename2形式的命令行运行，将文件filename2的内容附加在文件filename1之后。
// file linked program.
#include <stdio.h>
#define SIZE 512
void main(int argc,char *argv[])
{ char buffer[SIZE]; FILE *fp1,*fp2; if(argc!=3) { printf("Usage: linkfile filename1 filename2\n"); return; } // 按追加方式打开argv[1] 所指文件
 if((fp1=fopen(argv[1],"a"))==NULL) { printf("The file %s can not be opened.\n",argv[1]); return; } if((fp2=fopen(argv[2],"r"))==NULL) { printf("The file %s can not be opened.\n",argv[2]); return; } // 读入一行立即写出，直到文件结束
 while(fgets(buffer,SIZE,fp1)!=NULL) printf("%s\n",buffer); while(fgets(buffer,SIZE,fp2)!=NULL) fputs(buffer,fp1); fclose(fp1); fclose(fp2); if((fp1=fopen(argv[1],"r"))==NULL) { printf("The file %s can not be opened.\n",argv[1]); return; } while(fgets(buffer,SIZE,fp1)!=NULL) printf("%s\n",buffer); fclose(fp1);
}

int fprintf(FILE *fp,char *format,arg_list)

//存储文件名：save.txt
//程序代码如下：
// file display program.
#include <stdio.h>
void main()
{ char name[10]; int nAge,nClass; long number; FILE *fp; if((fp=fopen("student.txt","w"))==NULL) { printf("The file %s can not be opened.\n","student.txt"); return; } fscanf(stdin,"%s %d %d %ld",name,&nClass,&nAge,&number); fprintf(fp,"%s %5d %4d %8ld",name,nClass,nAge,number); fclose(fp); if((fp=fopen("student.txt","r"))==NULL) { printf("The file %s can not be opened.\n","student.txt"); return; } fscanf(fp,"%s %d %d %ld",name,&nClass,&nAge,&number); printf("name nClass nAge number\n"); fprintf(stdout,"%-10s%-8d%-6d%-8ld\n",name,nClass,nAge,number); fclose(fp);
}

int fread(void *buffer,unsigned sife,unsigned count,FILE *fp)

int fwrite(void *buffer,unsigned sife,unsigned count,FILE *fp)

#include <stdio.h>
#define SIZE 4
struct worker
{ int number; char name[20]; int age;
};
void main()
{ struct worker wk; int n; FILE *in,*out; if((in=fopen("file1.txt","rb"))==NULL) { printf("The file %s can not be opened.\n","file1.txt"); return; } if((out=fopen("file2.txt","wb"))==NULL) { printf("The file %s can not be opened.\n","file2.txt"); return; } while(fread(&wk,sizeof(struct worker),1,in)==1) fwrite(&wk,sizeof(struct worker),1,out); fclose(in); fclose(out);
}

int getw(FILE *fp)

#include <stdio.h>
void main(int argc,char *argv[])
{ int i,sum=0; FILE *fp; if(argc!=2) { printf("Command error,Usage: readfile filename\n"); exit(1); } if(!(fp=fopen(argv[1],"rb"))) { printf("The file %s can not be opened.\n",argv[1]); exit(1); } for(i=1;i<=10;i++) sum+=getw(fp); printf("The sum is %d\n",sum); fclose(fp);
}

int putw(int n,FILE *fp)

#include <stdio.h>
void main(int argc,char *argv[])
{ int i; FILE *fp; if(argc!=2) { printf("Command error,Usage: writefile filename\n"); return; } if(!(fp=fopen(argv[1],"wb"))) { printf("The file %s can not be opened.\n",argv[1]); return; } for(i=1;i<=10;i++) printf("%d\n", putw(i,fp)); fclose(fp);
}

int feof(FILE *fp)

#include <stdio.h>
void main(int argc,char *argv[])
{ FILE *in,*out; char ch; if(argc!=3) { printf("Usage: copyfile filename1 filename2\n"); return; } if((in=fopen(argv[1],"rb"))==NULL) { printf("The file %s can not be opened.\n",argv[1]); return; } if((out=fopen(argv[2],"wb"))==NULL) { printf("The file %s can not be opened.\n",argv[2]); return; } while(!feof(in)) { ch=fgetc(in); if(ferror(in)) { printf("read error!\n"); clearerr(in); } else { fputc(ch,out); if(ferror(out)) { printf("write error!\n"); clearerr(out); } } } fclose(in); fclose(out);
}

int ferror(FILE *fp)

void clearerr(FILE *fp)

#include <stdio.h>
void main(int argc,char *argv[])
{ FILE *in,*out; char ch; if(argc!=3) { printf("Usage: copyfile filename1 filename2\n"); return; } if((in=fopen(argv[1],"rb"))==NULL) { printf("The file %s can not be opened.\n",argv[1]); return; } if((out=fopen(argv[2],"wb"))==NULL) { printf("The file %s can not be opened.\n",argv[2]); return; } while(!feof(in)) { ch=fgetc(in); if(ferror(in)) { printf("read error!\n"); clearerr(in); } else { fputc(ch,out); if(ferror(out)) { printf("write error!\n"); clearerr(out); } } } fclose(in); fclose(out);
}

long ftell(FILE *fp)

void rewind(FILE *fp)

#include <stdio.h>
void main()
{ FILE *in,*out; in=fopen("filename1","r"); out=fopen("filename2","w"); while(!feof(in)) fputc(fgetc(in),out); rewind(out); while(!feof(in)) putchar(fgetc(in)); fclose(in); fclose(out);
}

int fseek(FILE *fp,long offset,int base)

#include <stdio.h>
#include <string.h>
struct std_type
{ int num; char name[20]; int age; char class;
}stud;
int cstufile()
{ int i; FILE *fp; if((fp=fopen("stufile","wb"))==NULL) { printf("The file can't be opened for write.\n"); return 0; } for(i=1;i<=100;i++) { stud.num=i; strcpy(stud.name,"aaaa"); stud.age=17; stud.class='8'; fwrite(&stud,sizeof(struct std_type),1,fp); } fclose(fp); return 1;
}
void main()
{ int n; FILE *fp; if(cstufile()==0) return; if((fp=fopen("stufile","rb"))==NULL) { printf("The file can not be opened.\n"); return; } for(n=0;n<100;n+=2) { fseek(fp,n*sizeof(struct std_type),SEEK_SET); fread(&stud,sizeof(struct std_type),1,fp); printf("%10d%20s%10d%4c\n",stud.num,stud.name,stud.age,stud.class); } fclose(fp);
}

void exit(int status)

int feof(FILE *fp)