我是新来的，所以我不知道我是否正确发布了此信息。我做了老师告诉我们为这个项目要做的一切，但是最后一个让我难住了，因为我们从来没有在类里面谈论过排序。它说:“修改 print() 函数，使其显示按零件号升序排列的零件。”我试着翻阅书本和上网，但结果却让自己变得更加困惑。谁能帮我？这是我的代码:
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define NAME_LEN 25
#define MAX_PARTS 100
struct part {
int number;
char name[NAME_LEN + 1];
int on_hand;
float price;
};
int find_part(int number, const struct part inv[], int np);
void insert(struct part inv[], int *np);
void search(const struct part inv[], int np);
void update(struct part inv[], int np);
void print(const struct part inv[], int np);
int read_line(char [], int);
/**************************************************************
* main: Prompts the user to enter an operation code, *
* then calls a function to perform the requested *
* action. Repeats until the user enters the *
* command 'q'. Prints an error message if the user *
* enters an illegal code. *
**************************************************************/
int main(void)
{
char code;
struct part inventory[MAX_PARTS];
int num_parts = 0;
for (;;)
{
printf("Enter operation code: ");
scanf(" %c", &code);
while (getchar() != '\n') /* skips to end of line */
{
;
}
switch (code)
{
case 'i':
insert(inventory, &num_parts);
break;
case 's':
search(inventory, num_parts);
break;
case 'u':
update(inventory, num_parts);
break;
case 'p':
print(inventory, num_parts);
break;
case 'q':
return 0;
default:
printf("Illegal code\n");
break;
}
printf("\n");
}
}
/************************************************************
* find_part: Looks up a part number in the inv array. *
* Returns the array index if the part number *
* is found; otherwise, returns -1. *
************************************************************/
int find_part(int number, const struct part inv[], int np)
{
int i;
for (i = 0; i < np; i++)
{
if (inv[i].number == number)
{
return i;
}
}
return -1;
}
/****************************************************************
* insert: Prompts the user for information about a new *
* part and then inserts the part into the inv *
* array. Prints an error message and returns *
* prematurely if the part already exists or the *
* array is full. *
****************************************************************/
void insert(struct part inv[], int *np)
{
int part_number;
if (*np == MAX_PARTS)
{
printf("Database is full; can't add more parts.\n");
return;
}
printf("Enter part number: ");
scanf("%d", &part_number);
if (find_part(part_number, inv, *np) >= 0)
{
printf("Part already exists.\n");
return;
}
inv[*np].number = part_number;
printf("Enter part name: ");
read_line(inv[*np].name, NAME_LEN);
printf("Enter quantity on hand: ");
scanf("%d", &inv[*np].on_hand);
printf("Enter the price of the item: ");
scanf("%f", &inv[*np].price);
(*np)++;
}
/************************************************************
* search: Prompts the user to enter a part number, then *
* looks up the part in the inv array. If the *
* part exists, prints the name and quantity on *
* hand; if not, prints an error message. *
************************************************************/
void search(const struct part inv[], int np)
{
int i, number;
printf("Enter part number: ");
scanf("%d", &number);
i = find_part(number, inv, np);
if (i >= 0)
{
printf("Part name: %s\n", inv[i].name);
printf("Quantity on hand: %d\n", inv[i].on_hand);
printf("Item Price: %.2f\n", inv[i].price);
}
else
{
printf("Part not found.\n");
}
}
/*************************************************************
* update: Prompts the user to enter a part number. *
* Prints an error message if the part can't be *
* found in the inv array; otherwise, prompts the *
* user to enter change in quantity on hand and *
* updates the array. *
*************************************************************/
void update(struct part inv[], int np)
{
int i, number, change, userChoice, changePartNum;
float changePrice;
char *changeName[] = {""};
printf("Enter part number: ");
scanf("%d", &number);
i = find_part(number, inv, np);
if (i >= 0)
{
printf("Enter your selection to edit this particular part:\n"
"\t\t Type 1 to change the Part Number\n"
"\t\t Type 2 to change the Part Name\n"
"\t\t Type 3 to change the Price\n"
"\t\t Type 4 to change the Quantity on Hand\n"
"\t\t Type 5 to exit without making changes\n\n"
"\t\t Enter your choice here: ");
scanf("%d", &userChoice);
switch ( userChoice )
{
//printf("Would you like to change the Part Number? \nType 1 for yes or 2 for no.");
//scanf("%d", &userChoice);
case 1:
printf("Enter new part number: ");
scanf("%d", &changePartNum);
inv[i].number = changePartNum;
printf("Change part num: %d\n", changePartNum);
printf("inv[i].number: %d\n", inv[i].number);
break;
//printf("Would you like to change the Part Name? \nType 1 for yes or 2 for no.");
//scanf("%d", &userChoice);
case 2:
printf("Enter new name of part: ");
scanf("%s", changeName);
printf("Change part name: %s\n", changeName);
//strcpy (*changeName, inv[i].name[NAME_LEN + 1]);
//printf("&inv[i].name[NAME_LEN + 1]: %d\n", &inv[i].name[NAME_LEN + 1]);
break;
//printf("Would you like to change the price? \nType 1 for yes or 2 for no.");
//scanf("%d", &userChoice);
case 3:
printf("Enter change in item price: ");
scanf("%f", &changePrice);
inv[i].price = changePrice;
break;
//printf("Would you like to change the quantity on hand? \nType 1 for yes or 2 for no.");
//scanf("%d", &userChoice);
case 4:
printf("Enter change in quantity on hand: ");
scanf("%d", &change);
inv[i].on_hand = change;
break;
case 5:
printf("Exiting the editor.");
break;
default:
printf("Your choice is not on the list.");
break;
}
}
else
{
printf("Part not found.\n");
}
}
/************************************************************
* print: Prints a listing of all parts in the inv array, *
* showing the part number, part name, and *
* quantity on hand. Parts are printed in the *
* order in which they were entered into the *
* array. * *
************************************************************/
void print(const struct part inv[], int np)
{
int i;
printf("Part Number Part Name "
"Quantity on Hand "
" Price\n");
for (i = 0; i < np; i++)
{
printf("%7d\t\t %-5s%31d\t%.2f\n", inv[i].number,
inv[i].name, inv[i].on_hand, inv[i].price);
}
}
/*************************************************************
* read_line: Skips leading white-space characters, then *
* reads the remainder of the input line and *
* stores it in str. Truncates the line if its *
* length exceeds n. Returns the number of *
* characters stored. *
*************************************************************/
int read_line(char str[], int n)
{
int ch = 0;
int i = 0;
while (isspace (ch = getchar()))
{
;
}
while (ch != '\n' && ch != EOF)
{
if (i < n)
{
str[i++] = ch;
}
ch = getchar();
}
str[i] = '\0';
return i;
}
最佳答案
如果您的教授允许您使用标准库中的函数，请查看 C library function to do sort ，它提供了一个答案，向您展示如何使用 qsort()。如果您使用的是 Linux，您还可以通过执行 man qsort 来获取有关该函数(以及其他标准库函数)的文档。 。如果您使用的不是 Linux，请查看各种在线手册页。
如果没有，您的教授可能希望您自己进行研究。通常，冒泡排序算法因其简单性而被教授给初学者。 rosettacode提供了冒泡排序的伪代码:
repeat
hasChanged := false
decrement itemCount
repeat with index from 1 to itemCount
if (item at index) > (item at (index + 1))
swap (item at index) with (item at (index + 1))
hasChanged := true
until hasChanged = false
请注意，在您的打印函数中，您已经拥有了所需的一切:数组及其长度。您通过循环遍历并打印出所有成员变量来演示了这一点。现在您只需要编写排序算法即可。该算法需要的一件事是比较器函数。您说您需要按零件号排序。这意味着您的比较器函数可能如下所示:
int compare(struct part a, struct part b)
{
return (a.number < b.number);
}
对于qsort():
qsort(inv, np, sizeof(part), compare);
在您的排序算法中(您应该自己编写):
if (item.number at index) > (item.number at (index + 1))
关于C - 按零件编号升序显示零件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26027640/