c 标准io

读文件到文件尾

    FILE *file;

    if((file = fopen("D://a.txt","r")) == NULL)

    {

        printf("cant open file!");

    }

    char ch;

    while((ch = fgetc(file))!=EOF) putchar(ch);

    if(fclose(file)) printf("file close error!");

从键盘输入字符存入文件

    FILE *file;

    if((file = fopen("D://a.txt","w")) == NULL)

    {

        printf("cant open file!");

    }

    char ch;

    while((ch = fgetchar()!='\n')) fputc(ch,file);

    if(fclose(file)) printf("file close error!");

读写字符串

char * fgets(char *str,int num,FILE *file)

char * fputs(char *str,FILE *file)

#include <stdio.h>

#include <string.h>

main(){

    FILE * fp1, *fp2;

    char str[128];

    if((fp1 = fopen("text1.txt","r"))==NULL)

    {

        /*以只读方式打开文件1*/

        printf("can not open file \n")

        exit(0);

    }

    if((fp2 = fopen("test2.txt","w")) == NULL){

        /*以只写方式打开文件2*/

        printf("can not open file\n");

        exit(0);        

    }

    while((strlen(fgets(str,128,fp1)))>0)

    /*从文件中读回字符串长如大于0*/

    printf("%s",str);

    /*在屏幕显示*/

    fclose(fp1);

    fclose(fp2);

}

获取文件长度

    fseek (file, 0, SEEK_END);   // non-portable

    int size=ftell (file);

    rewind (file);

成块读写文件

fread

fwrite