c - 出于某种原因，printf 函数在我要显示的内容上添加了一个空格

Question

我试图在列中显示文本，但在输出的第二行添加了一个空格。我做错了什么吗？ (条目在字符串前不包含空格)以下是涉及的函数:

add(List *book)
{
    Contact *runner = book->una;
    Contact *node = (Contact *) malloc(sizeof(Contact));

if (node == NULL);
else {
    printf("Add a contact\n");
    printf("Enter the first name: ");
    scanf("%s", node->fname);
    printf("Enter the last name: ");
    scanf("%s", node->lname);
    printf("Enter the mobile number: ");
    scanf("%s", node->number);
    printf("\nContact added!\n\n");
    node -> next = NULL;
    if(book->una == NULL){
        book->una = node;
    }
    else
    {
        while( runner->next != NULL)
        {
            runner = runner->next;
        }
        runner->next = node;
    }
}
}

    display(List *book)
{
    Contact *runner = book -> una;
    if(runner == NULL)
    {
        printf("%20s", "PHONEBOOK EMPTY!");
        return;
    }
    printf("Contact list\n");
    printf("%-15s%-15s%-15s", "First Name", "Last Name", "Mobile number\n");
    while( runner != NULL)
    {
        printf("%-15s%-15s%-15s\n", runner->fname, runner->lname, runner->number);
        runner = runner->next;
    }
}

/*An example output basically turns out like this:

First Name         Last Name         Mobile Number
 James              Harrison          123456
Wendy              Barnes            00000
Cam                Rodriguez         575938*/

任何输入数据都将如上所示打印。

Answer 1

您应该将 \n 放在格式字符串中而不是字段中。由于 Mobile number 有 13 个字符，加上 \n 14 并添加一个空格作为 %-15s 的填充，它位于\n 因此，在下一行。