C语言基础文件读写操作

整理了一份C语言的文件读写件操作代码，测试时打开相应的注释即可。

 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>

 /*
  * EOF: 符号常量，其值为-1.
  * fgets() 最多读取int-1个字符，遇换行或EOF即返回.
  * fputs() 写文件时，忽略字符串截止符'\0'.
  * fread()和fwrite() 数据块读写，多用于结构体数组（顺序存储的结构体）.
  *
  * 函数原型：
  * 读：
  * int fgetc(FILE *stream);
  * char *fgets(char *s, int size, FILE *stream);
  * size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
  * int fscanf(FILE *stream, const char *format, ...);
  * 写：
  * int fputc(int c, FILE *stream);
  * int fputs(const char *s, FILE *stream);
  * size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
  * int fprintf(FILE *stream, const char *format, ...);
  * 其他：
  * void rewind(FILE *stream); 将文件内部的位置指针重新指向一个流（数据流/文件）的开头.
  *
  * 打开方式：
  * r(read): 读
  * w(write): 写
  * a(append): 追加
  * +: 读和写
  * t(text): 文本文件，可省略不写
  * b(banary): 二进制文件
  */

 FILE *fp = NULL;

 // READ
 void GetCharFromFile(FILE *fp)
 {
     int ch = ;

     while ((ch=fgetc(fp)) != EOF)    //失败时返回 EOF
     {
         printf("fget: [%c]\n", ch);
     }
 }

 void GetLineFromFile(FILE *fp)
 {
     char line[] = "";

     while (fgets(line, sizeof(line), fp) != NULL)    //失败时返回 NULL
     {
         printf("fgets: [%s]\n", line);
     }
 }

 void GetBlockFromFile(FILE *fp)
 {
     int i = ;
     int block[] = {};
     int count = ;

     while (fread(block, sizeof(block), count, fp) == count)    //失败时返回值 != count
     {
         printf("fread: ");
         for (i=; i<; i++)
         {
             printf("%d ", block[i]);
         }
         printf("\n");
     }
 }

 void ReadFormatToFile(FILE *fp)
 {
     char file[] = "";
     char func[] = "";
     char date[] = "";
     int  line = ;

     fscanf(fp, "%s %s %d %[^\n]", file, func, &line, date);    //返回读取元素个数，eg:4
     printf("file: %s\n", file);
     printf("func: %s\n", func);
     printf("line: %d\n", line);
     printf("date: %s\n", date);
 }

 // WRITE
 int WriteCharToFile(FILE *fp, char ch)
 {
     int ret = ;

     ret = fputc(ch,fp);            //失败时返回EOF
     return ret!=EOF?:-;
 }

 int WriteStrToFile(FILE *fp, char *str)
 {
     int ret = ;

     ret = fputs(str, fp);
     return ret!=EOF?:-;        //失败时返回EOF
 }

 int WriteBlockToFile(FILE *fp, const void *block, int size, int count)
 {
     int ret = ;

     ret = fwrite(block, size, count, fp);    //失败时返回值 != count
     return ret!=count?-:;
 }

 int WriteFormatToFile(FILE *fp)
 {
     int ret = ;

     ret = fprintf(fp, "%s %s %d %s\n", __FILE__, __func__, __LINE__, __DATE__);
     return ret<?-:;            //失败时返回一个负值
 }

 // MAIN
 int main(int argc, char **argv)
 {
     char ch = 'r';
     char *str = "Hello World.\n";
     int block[] = {,,,,,,,,,};
     char *filePath = "./ll";

     fp = fopen(filePath, "w+");        //不关心文件存在与否，每次重写文件，并可读
     if (NULL == fp)
     {
         perror("fopen");
         return -;
     }

     // WRITE
     // printf("WriteCharToFile: %s\n", WriteCharToFile(fp, ch)?"Fail":"Success");
     printf("WriteStrToFile: %s\n", WriteStrToFile(fp, str)?"Fail":"Success");
     // printf("WriteBlockToFile: %s\n", WriteBlockToFile(fp, block, sizeof(block), 1)?"Fail":"Success");
     // printf("WriteFormatToFile: %s\n", WriteFormatToFile(fp)?"Fail":"Success");

     rewind(fp);
     // READ
     // GetCharFromFile(fp);
     GetLineFromFile(fp);
     // GetBlockFromFile(fp);
     // ReadFormatToFile(fp);

     fclose(fp);
     return ;
 }