如何在以下代码中添加 Y/N？

Question

I am learning from C Programming Absolute Beginner's Guide. I had to do the following exercise and I took it upon myself to try to add a:

"Would you like to sort these numbers in ascending order? (Y/N): "

after the numbers are randomly generated. However, I am struggling with this. I have tried if, else if, do while, etc. But I am struggling with it. How would you add that to this code?

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

int main()
{
    int ctr, inner, outer, didSwap, temp, choice;
    int nums[10];
    time_t t;

    srand(time(&t));

    //First step is to fill the array with random numbers (from 1 to 10)

    for (ctr = 0; ctr < 10; ctr++)
    {
        nums[ctr] = (rand() % 99 + 1);
    }

    //Now list the array as it currently is before sorting

    puts("\nHere is the list before the sort:");
    for (ctr = 0; ctr < 10; ctr++)
    {
        printf("%d\n", nums[ctr]);
    }

    //Now sort the array

    for (outer = 0; outer < 10; outer++)
    {
        didSwap = 0; //Becomes 1 (true) if list is not yet ordered
        for (inner = outer; inner < 10; inner++)
        {
            if (nums[inner] < nums [outer])
            {
                temp = nums[inner];
                nums[inner] = nums [outer];
                nums[outer] = temp;
                didSwap = 1;
            }
        }
        if (didSwap == 0)
        {
            break;
        }
    }

        //Now list the array as it currently is after sorting

        puts("\nHere is the list after the sort:");
        for (ctr = 0; ctr <10; ctr++)
        {
            printf("%d\n", nums[ctr]);
        }


    return 0;
}

EDITED CODE:

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

int main()
{
    int ctr, inner, outer, didSwap, temp, choice;
    int nums[10];
    time_t t;

    srand(time(&t));

    //First step is to fill the array with random numbers (from 1 to 10)

    for (ctr = 0; ctr < 10; ctr++)
    {
        nums[ctr] = (rand() % 99 + 1);
    }

    //Now list the array as it currently is before sorting

    puts("\nHere is the list before the sort:");
    for (ctr = 0; ctr < 10; ctr++)
    {
        printf("%d\n", nums[ctr]);
    }

    puts("Would you like to sort in ascending order? ");
    puts(("(Reply Y or N): "));
    scanf(" %d", choice);
    choice = toupper(choice);

    if (choice = 'Y')
    {
        //Now sort the array

        for (outer = 0; outer < 10; outer++)
        {
            didSwap = 0; //Becomes 1 (true) if list is not yet ordered
            for (inner = outer; inner < 10; inner++)
            {
                if (nums[inner] < nums [outer])
                {
                    temp = nums[inner];
                    nums[inner] = nums [outer];
                    nums[outer] = temp;
                    didSwap = 1;
                }
            }
            if (didSwap == 0)
            {
                break;
            }
        }

        //Now list the array as it currently is after sorting

        puts("\nHere is the list after the sort:");
        for (ctr = 0; ctr <10; ctr++)
        {
            printf("%d\n", nums[ctr]);
        }
    }
    else if (choice = 'N')
    {
        puts("Have a good day!");
    }


    return 0;
}

Answer 1

• You should use %c format specifier with char variable to read one character.
• You will have to use unary & operator to get a pointer to a variable for scanf() .
• = is an assignment operator in C. You should use == operator to check equality.

    /* remove choice from int variable declaration */

    char choice; /* use char */
    puts(("(Reply Y or N): "));
    scanf(" %c", &choice); /* use %c and & */
    choice = toupper(choice);

    if (choice == 'Y') /* use == */
    {
        //Now sort the array
        /* omit */
    }
    else if (choice == 'N') /* use == */
    {
        puts("Have a good day!");
    }