/*試卷管理，修改試卷內容*/
ModifyPaper()
{
 FILE *fp;
    char paperchar;
    char choose;
    char paperfile[20]="";/*用戶選擇的試卷名*/
    /*試卷選擇界面*/
    printf("\nplease choose the paper to modify:\n");
    printf("+++++++++++++++++++\n");
    printf("+ a | paper1.txt  +\n");
    printf("+ b | paper2.txt  +\n");
    printf("+ c | paper3.txt  +\n");
    printf("+ d | paper4.txt  +\n");
    printf("enter your choose here:");
    scanf("%c",&choose);  /*獲取用戶選項*/
    getchar();
    /*放到存儲試卷名稱的變量中*/
    switch(choose)
        {
        case 'a':
            strcpy(paperfile,"paper1.txt");
            break;
        case 'b':
            strcpy(paperfile,"paper2.txt");
            break;
        case 'c':
            strcpy(paperfile,"paper3.txt");
            break;
        case 'd':
            strcpy(paperfile,"paper4.txt");
            break;
        }
    /*打開試卷文件，以寫的方式打開*/
    fp=fopen(paperfile,"w");
    if(fp==NULL)
    {
        printf("\n Open file fail!End with any key.\n");
        perror("Open file fail");
        getch();
        exit(1);
    }
    /*輸入要修改的試卷內容，寫入試卷文件*/
    printf("please input the paper content here,end with #:");
    paperchar=getchar();
    while(paperchar!='#')
    {

    fputc(paperchar,fp);
    paperchar=getchar();
    }
    fclose(fp);
    /*打開試卷文件，顯示修改后的內容*/
    fp = fopen(paperfile,"r");/*以讀方式打開文件*/
    if (fp == NULL)
    {
        printf("\n Open file fail!End with any key.\n");
        perror("Open file fail");
        getch();
        exit(1);
    }
    printf("the %s's content after modify is:\n",paperfile);
    paperchar=fgetc(fp);/*讀取第一個字符*/

    while(paperchar!=EOF)
        {
        printf("%c",paperchar);

        paperchar=fgetc(fp);

        }
    printf("\n");
    fclose(fp);
}