在一个文件末尾增加字符串，并在控制台打印出来

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

int main()
{
    FILE *fp_write, *fp_read;
    char ch;
    char add[] = "An extra line
";

    fopen_s(&fp_write,"E:\first.txt","a+");
    if(fp_write == NULL)
    {
        printf("Can't open the file!
");
        system("pause");
        return 0;
    }
    //定位到文件末尾
    fseek(fp_write,0,SEEK_END);
    fputs(add,fp_write);
    //fwrite(add,sizeof(add),1,fp_write);
    //先关闭写入流再打开读出流
    fclose(fp_write);

    fopen_s(&fp_read,"E:\first.txt","r");
    if(fp_read == NULL)
    {
        printf("fp_read,Can't open the file!
");
        system("pause");
        return 0;
    }
    while((ch = fgetc(fp_read)) != EOF)
        putchar(ch);

    fclose(fp_read);

    system("pause");
    return 0;
}