我想确保我的程序是正确的，这是 c 编程

Question

i just wanted to make sure my formula was correct and wanted to see if there is a way to make the height go all the way to zero and the time count with it here is my code so far i have ran it with some numbers like height is 10 and velocity is 0 and it will start the time count at 0.0 and increment in .25 and the height will start at 10 but it will not count down to zero for the height and will stop at .75 for the time im sorry if its confusing what im trying to explain bc im confused my self

// Programmer:      Your Name
// Date:            Date
// Program Name:    The name of the program
// Chapter:         Chapter # - Chapter name
// Description:     2 complete English sentences describing what the program does,
//                  algorithm used, etc.

#define _CRT_SECURE_NO_WARNINGS // Disable warnings (and errors) when using non-secure versions of printf, scanf, strcpy, etc.
#include <stdio.h> // Needed for working with printf and scanf
#include <math.h>
int main(void)
{
    // Constant and Variable Declarations
    double startingHeight = 0.0;
    double heightBall = 0.0;
    double volicetyBall = 0.0;
    double ballTime = 0.0;
    double downTime = 0.25;
    double maxHeight = 0.0;
    double timeLast = 0.0;



    // *** Your program goes here ***
    do {
        printf("\n Enter initial height of the ball (in ft.): ");
        scanf("%lf", &startingHeight);

        if (startingHeight < 0) {
            printf("\t The initial height must be greater than or equal to 0");
        }


    } while (startingHeight < 0);

    do {
        printf("\n Enter initial velocity of the ball (in ft. per sec.): ");
        scanf("%lf", &volicetyBall);

        if (volicetyBall < 0) {
            printf("\t The initial velocity must be greater than or equal to 0");
        }

    } while (volicetyBall < 0);

    printf("\n");
    printf("Time\tHeight\n");
    if (startingHeight < 0 && volicetyBall > 0) {
        printf("%0.2f\t%0.1f\n", ballTime, startingHeight);
    }


    else {

        do {

            heightBall = startingHeight + volicetyBall * ballTime - 16 * pow(ballTime, 2);

            if (maxHeight < heightBall) {
                maxHeight = heightBall;
            }


            if (heightBall >= 0) {
                printf("%0.2f\t%0.1f\n", ballTime, heightBall);
                timeLast = ballTime;
            }

            ballTime = ballTime + downTime;
        } while (heightBall >= 0);

    }

    printf("\n The maximum height the ball will reach is %0.1f feet\n", maxHeight);
    printf("\n The time for the ball to reach the ground is %0.2f seconds\n", timeLast);

    printf("\n");



    return 0;
} // end main()

Answer 1

Yes, it's C, but C that invites Undefined Behavior for failing to validate the user input. What happens in your code if the user slips and hits 'r' instead of '5' when entering the height of the ball?

To prevent and recover from an invalid input you need to check the return of your input function and empty stdin of any offending characters before your next attempted read, eg

    /* validate every input */
    if (scanf ("%lf", &startingHeight) != 1) {
        int c;
        fputs ("error: invalid input.\n", stderr);
        do  /* read offending chars until '\n' or EOF */
            c = getchar();
        while (c != '\n' && c != EOF);
        continue;
    }

All though with a do .... while (...) you simply jump to the end of the loop and your startingHeight < 0 test false and you skip to the velocity question, better to:

for (;;) {  /* loop continually until valid input */
    printf ("\n Enter initial height of the ball (in ft.): ");
    /* validate every input */
    if (scanf ("%lf", &startingHeight) != 1) {
        int c;
        fputs ("error: invalid input.\n", stderr);
        do  /* read offending chars until '\n' or EOF */
            c = getchar();
        while (c != '\n' && c != EOF);
        continue;
    }

    if (startingHeight < 0) {
        printf ("\t The initial height must be greater than or equal to 0");
        /* you should empty stdin here as well -- hint: create a function */
    }
    else
        break;
}

That way you re-ask the height question until you have a valid startingHeight >= 0 .

Other nit, don't use printf to output a single-character, that is what putchar or fputc is for, eg

// printf ("\n");      /* replace this with... */
putchar ('\n');

Also, no need for two- printf calls (you are not performing any conversions) where a single puts will do, eg

// printf("\n");
// printf("Time\tHeight\n");
puts ("\nTime\tHeight");

Otherwise, aside from the normal beginning failure to validates, you are doing fairly well.