c - 无法修复数组排序和输出

Question

我正在创建一个似乎可以正常运行的评分计算器。但是，当数组排序时，当输入中没有“0”时，它会输出“0”作为我的数组值之一。如果用户想要计算 0 分，我也无法设置标志(不是退出语句)来结束程序。

我尝试过更改初始化值、更改冒泡排序中分配的值，并使用各种输入多次运行程序。总的来说，我对编程还很陌生，答案可能就在眼前，但我似乎无法解决。

#include <stdio.h>

int main (void)
{


    /* Declare variables */
    /* ----------------- */

    int number_of_grades;
    int quit;
    int g;
    int grades[10] = {0};
    int grade_total = 0;
    int temp;
    int highest_grade;
    int lowest_grade;
    float average_grade;
    char changed = 'T';
    char c;

    /* Output initial greeting and prompt user for the number of grades to be entered, making sure the user enters 1-10 grades. If they enter a 0, exit the program. If they enter a number above 10, reprompt. */
    /* -------------------------------------------------------------------------------------------------------------------------------- */

    printf ( "Welcome to the Grade Calculator\n" );

    quit = 1;
    while (quit == 1)

    do
    {
        printf ( "\nEnter the number of grades to be processed (0 - 10): " );
        scanf ( "%i", &number_of_grades );
        while ( (c = getchar() != '\n') && c != EOF );

        if ( number_of_grades == 0)
            quit = 0;
        else if ( number_of_grades > 10 )
            printf ( "\n *** Invalid number of grades entered. ***\n" );
    } while ( number_of_grades > 10 );

    /* Prompt user to enter the grades. Ensure the grade is between 0-100. If not, reprompt. */
    /* ------------------------------------------------------------------------------------- */

    for ( g = 1; g <= number_of_grades; g++ )
    {
        do
        {
            printf ( "\nEnter grade for student #%i: ", g );
            scanf ( "%i", &grades [g] );
            while ( (c = getchar() != '\n') && c != EOF );

            if ( grades [g] < 0 || grades [g] > 100 )
                printf ( "\n***Invalid Entry. Grade must be 0 to 100.***\n" );
        } while ( grades [g] < 0 || grades [g] > 100 );

            grade_total = grade_total + grades[g];
        }

    /* Calculate the average grade */
    /* --------------------------- */

    average_grade = (float) grade_total / number_of_grades;

    /* Sort the array from lowest to highest grade. */
    /* -------------------------------------------- */

    while ( changed == 'T' )
    {
        changed = 'F';

        for ( g = 1; g < number_of_grades; g++ )
        {
            if ( grades [g] > grades [g + 1])
            {
                temp = grades [g];
                grades [g] = grades [g + 1];
                grades [g + 1] = temp;

                changed = 'T';
            }
        }
    }

    /* Calculate the lowest and highest grades input by the user */
    /* --------------------------------------------------------- */

    lowest_grade = grades[1];
    highest_grade = grades [g-1];

    /* Output the lowest grade, the highest grade, the average grade, and the grades sorted in ascending order to the user. */
    /* -------------------------------------------------------------------------------------------------------------------- */

    printf ( "\nThe minimum grade is %i", lowest_grade );
    printf ( "\nThe maximum grade is %i", highest_grade );
    printf ( "\nThe class average is %.1f\n", average_grade );

    printf ( "\nThe %i grades entered are:\n\n", number_of_grades );
    for ( g = 0; g < number_of_grades; g++ )
        printf ( "%i ", grades [g] );
    printf ( "\n" );



    printf ( "\nThank you for using the Grade Calculator\n" );

        getchar();

} /* End main */

回复:排序数组:当我输入三个等级(例如:100、98、92)时，它输出一个排序数组“0、92、98”。Re: Quit Statement for input of "0"grades to calculate: 当程序提示输入等级数并输入“0”时，输出仍然包括最终的最小值、最大值、平均值和排序数组语句，而不仅仅是最终的问候语。

Answer 1

在C语言中，数组索引从0开始结束于 size-1 .

但是您正在使用来自 1 的数组至 size .

可能当用户将“number_of_grades”设为 10 时，您将访问 array[10]这超出了范围，因为数组大小为 10，并且该内存可能有一些垃圾值。

所以您可以通过更新您的 for 循环来解决这个问题。变化

for ( g = 1; g <= number_of_grades; g++ )

到

for ( g = 0; g < number_of_grades; g++ )

无处不在。

注意:

(1) 一些地方array[g+1] array[g-1]存在。

您需要更新逻辑以便您只读/写 array[k]其中 0 <= k < size-1 .

(2) 您在评论中提到的初始循环问题:在 while 循环中有一个 do-while 循环。

while(1 ==  quit) 
{
   do{
   } while ( number_of_grades > 10)
}

我想你想做的是:

1. 如果用户输入超过 10 个，则告诉它是无效输入。给用户多一次机会。
2. 如果用户输入 0，则退出程序。

如果是这种情况，您可以执行以下操作。

//while(1 ==  quit)  //This is not required.
{
   do{
       scanf();
       if ( number_of_grades == 0)
       {
           //Print error
           return;
       }
       else if ( number_of_grades > 10 )
           printf ( "\n *** Invalid number of grades entered. ***\n" );
   } while ( number_of_grades > 10)
}

理想情况下，您应该为每个问题打开一个新帖子。否则，该帖子将变得困惑，并且无法供面临类似问题的其他人使用。