c - 如何用 cycle-for 和 scanf 填充我的结构数组的每个结构？

Question

我是这个网站的新手，它看起来很酷。

我有这个问题，我想制作一个程序，让用户决定要申报多少本书，接下来用户为每本请求的书填写信息(例如:用户想要 3 本书，所以他填写了所有信息这 3 本书)。

我想我需要一个数组结构，但我不知道如何循环完成这个填充过程。

这是我的代码:

struct book
    {
    char bname[20];
    int pages;
    char author[20];
    long price; 
};

printf("enter number of books to store");
scanf("%d",&unumber);
for (i=0;i<number_of_books;i++) {printf's and scanf's to fill each struct}

Answer 1

在循环中读取输入时，一个主要的关注领域是确保 stdin 在每次读取后被刷新，以防止尾随的 newline 被解释为下一次的输入读取语句。有很多方法可以做到这一点，但是，使用 scanf 最简单的方法是通过精心设计的 format 语句来处理尾随的 newline。下面说明了这种方法:

#include <stdio.h>

#define MAXS 256

struct book
{
    char bname[20];
    int pages;
    char author[20];
    long price; 
};

int main () {

    struct book books[MAXS] = {{ {0}, 0, {0}, 0 }}; /* initialize all values to zero (null) */
    int nbooks = 0;
    int i = 0;

    printf ("\nEnter number of books to store: ");
    scanf("%d%*c",&nbooks);                         /* read nbooks, and consume newline     */

    if (nbooks < 1) {                               /* validate number of books to enter    */
        fprintf (stderr, "error: invalid entry for 'nbooks'\n");
        return 1;
    }

    for (i = 0; i < nbooks; i++)                    /* enter values for each book, use      */
    {                                               /* scanf to read each value AND the     */
        printf ("\n  book[%2d] name  : ", i + 1);   /* newline character, emptying stdin    */
        scanf ("%[^\n]%*c", books[i].bname);        /* after each read.                     */
        printf ("  book[%2d] pages : ", i + 1);
        scanf ("%d%*c", &books[i].pages);
        printf ("  book[%2d] author: ", i + 1);
        scanf ("%[^\n]%*c", books[i].author);
        printf ("  book[%2d] price : ", i + 1);
        scanf ("%ld%*c", &books[i].price);
    }

    printf ("\n\nThe Books Entered Were:\n");       /* output info for each book entered    */
    i = 0;
    while (*books[i].bname)
    {
        printf ("\n  Book %-3d \"%s\"\n", i + 1, books[i].bname);
        printf ("    author : %s\n", books[i].author);
        printf ("    pages  : %d\n", books[i].pages);
        printf ("    price  : %ld\n", books[i].price);
        i++;
    }

    printf ("\n");

    return 0;
}

输出:

$ ./bin/books

Enter number of books to store: 2

  book[ 1] name  : Tom Sawyer
  book[ 1] pages : 321
  book[ 1] author: Mark Twain
  book[ 1] price : 2199

  book[ 2] name  : Huckelberry Finn
  book[ 2] pages : 298
  book[ 2] author: Mark Twain
  book[ 2] price : 1999


The Books Entered Were:

  Book 1   "Tom Sawyer"
    author : Mark Twain
    pages  : 321
    price  : 2199

  Book 2   "Huckelberry Finn"
    author : Mark Twain
    pages  : 298
    price  : 1999