Linux 打开文件并写入一段字符串，同一时候读出相应文件的信息--fopen()/fwrite()/fread()

/*
Test.c :create a file : Write a string to the file
   */

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

#define MAX   128

int
main(){
    FILE *fp = NULL;   //notice

    char  *filePath = "data/test.dat";

    char stringDes[] = "Hello world";
    stringDes[strlen(stringDes)] = ‘\0‘;
    char buf[MAX];
/*
   open a file :  FILE *fopen(const char *path, const char *mode);
 */
#if 1
    fp  = fopen(filePath,"at+");
    if(NULL == fp){
        perror("fp");
        return -1;
    }
    printf("file open success! \n");
#endif
/*
   write data block to a file:
       size_t fwrite(const void* buffer, size_t size, size_t count, FILE* stream);
   */
    int i;
    for(i = 0; i <= 2; i++){

        fwrite(stringDes,strlen(stringDes), 1, fp);
        fwrite("\n",1, 1, fp);

        fflush(fp);
    }

    printf("file set start \n");

    fseek(fp,0,SEEK_SET);  //set start file

    fread(buf,strlen(stringDes),1,fp);
    buf[strlen(stringDes)] = ‘\0‘;

    printf("buf = %s \n",buf);

    fclose(fp);
}