C中的for/while循环内存清除

Question

在我正在搞乱的程序中，它只是询问一个人编写了多少测试，然后返回一个平均值。不过我对其进行了一些修改，以便它询问输入的标记是否正确。

问题 1：它不允许您为所有测试输入分数
问题 2：如果标记错误，它会重新开始，但将先前的输入保留在内存中？我该如何解决？

代码如下：

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

int main(int argc, char *argv[]) {

    //int variables for grade
    unsigned int counter; //number of grades to be entered next
    int grade;
    int total;
    float average;
    // user input
    int userInput; // amount of tests
    int yesNo; 
    //amount of test passed
    unsigned int pass = 0;
    unsigned int fail = 0;
    int doCount = 1;
    //unsigned int test;

//---------------------------------------------------------------------------------------------------// 

    //standards for program to abide to
    total = 0; //Total amount of test to be set to zero, until while statement
    counter = 1; //Loop counter to start from one

//---------------------------------------------------------------------------------------------------// 

    printf ("Please enter amount of test you've written so far: ");
    scanf ("%d", &userInput);
    //printf ("%d", userInput);

//---------------------------------------------------------------------------------------------------//

    do {
        //Body of calculations of program
        for(counter = 0; counter <= userInput; ++counter) { //for loop that correlates to userInput for amount of passes and test marks
            printf ("Please enter percentage mark: "); //prompt for test mark
            scanf("%d", &grade);
            total = total + grade;
            counter = counter + 1;
            if (grade >= 40) {  //if statement for pass or fail
               pass = pass + 1;
            } else {
                 fail = fail + 1;
                }
        }//end of for loop
        printf ("Are the grades entered correct? (1 = yes, 2 = no): "); // user input for yesNo - are inputs correct    
        scanf ("%d", &yesNo);
        if (yesNo == 2) {

         } else {
            average = ((float)total / userInput); //Getting average for tests so far
                //if statement to clarify if you're passing
            if (average < 40) {
                printf ("\nYou are below sub minimum!\n");
                printf ("Your overall average is: %.2f %\n", average);
                printf ("Passed: %d\n", pass);
                printf ("Failed: %d", fail);
            } else if (average >= 75){
                printf ("\nYou have a distinction agregate!\n");
                printf ("Your overall average is: %.2f %\n", average);
                printf ("Passed: %d\n", pass);
                printf ("Failed: %d", fail);
            } else {
                printf ("\nYour overall average is: %.2f %\n", average);
                printf ("Passed: %d\n", pass);
                printf ("Failed: %d", fail);
            }
        doCount = 2;    
        }
    } while (doCount == 1);

    average = ((float)total / userInput); //Getting average for tests so far
//---------------------------------------------------------------------------------------------------//     

    getch ();
    return 0;
}

Answer 1

在您的 do while 循环中，当您第二次通过时，您需要重置您的变量。具体来说，总变量应重置为零。您第一次在 do while 循环之外执行此操作，但是一旦它在循环中进行第二次传递，它就不会重置为 0。 至于不读取所有测试输入，如果它要求 9 但您需要 10，那么它可能是 for 循环的问题。我通常使用 counter++ 而不是 ++counter，因为它在操作之后而不是在操作之前递增计数器。这可能是也可能不是我没有运行您的代码的原因，但值得一看。

Answer 2

我已编辑您的代码并评论了更改：

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

int main(int argc, char *argv[]) {

    //int variables for grade
    unsigned int counter; //number of grades to be entered next
    int grade;
    int total;
    float average;
    // user input
    int userInput; // amount of tests
    int yesNo;
    //amount of test passed
    unsigned int pass = 0;
    unsigned int fail = 0;
    int doCount = 1;
    //unsigned int test;

    //---------------------------------------------------------------------------------------------------// 

    //standards for program to abide to
    total = 0; //Total amount of test to be set to zero, until while statement
    counter = 0; //Loop counter to start from zero, It's always better to start from zero

                 //---------------------------------------------------------------------------------------------------// 

    printf("Please enter amount of test you've written so far: ");
    scanf("%d", &userInput);
    //printf ("%d", userInput);

    //---------------------------------------------------------------------------------------------------//

    do {
        //Body of calculations of program
        total = 0; //You need to reset total pass and fail
        pass = 0;
        fail = 0;
        for (counter = 0; counter < userInput; ++counter) { //for loop that correlates to userInput for amount of passes and test marks
            printf("Please enter percentage mark: "); //prompt for test mark
            scanf("%d", &grade);
            total = total + grade;
            //counter = counter + 1; You DON't need that
            if (grade >= 40) {  //if statement for pass or fail
                pass = pass + 1;
            }
            else {
                fail = fail + 1;
            }
        }//end of for loop
        printf("Are the grades entered correct? (1 = yes, 2 = no): "); // user input for yesNo - are inputs correct    
        scanf("%d", &yesNo);
        if (yesNo == 2) {

        }
        else {
            average = ((float)total / userInput); //Getting average for tests so far
                                                  //if statement to clarify if you're passing
            if (average < 40) {
                printf("\nYou are below sub minimum!\n");
                printf("Your overall average is: %.2f %\n", average);
                printf("Passed: %d\n", pass);
                printf("Failed: %d", fail);
            }
            else if (average >= 75) {
                printf("\nYou have a distinction agregate!\n");
                printf("Your overall average is: %.2f %\n", average);
                printf("Passed: %d\n", pass);
                printf("Failed: %d", fail);
            }
            else {
                printf("\nYour overall average is: %.2f %\n", average);
                printf("Passed: %d\n", pass);
                printf("Failed: %d", fail);
            }
            doCount = 2;
        }
    } while (doCount == 1);

    average = ((float)total / userInput); //Getting average for tests so far
                                          //---------------------------------------------------------------------------------------------------//     

    getch();
    return 0;
}