作业描述：

参考代码：

#include <stdio.h>

int GetAbsoluteValue(int num)//求绝对值
{
    return num > 0 ? num : -num;
}

double GetAbsoluteValue2(double num)
{
    return num > 0 ? num : -num;
}

double GetSqrt(double num)
{
    //此题进行一下扩展，原题是输入正整数，为了更加通用，改成输入一个正数
    const double eps = 1e-12;//定义结果的精度
    double x = 0, y = num / 2;
    while (GetAbsoluteValue2(y - x) >= eps)
    {
        x = y;
        y = (x + num / x) / 2;
    }
    return x;
}

void CalculateQuotientAndReminder(int dividend, int divisor)
{
    //思路：先判断符号是否同号，然后比较绝对值，然后不停的减去除数
    int quotient = 0;
    int remainder = 0;
    if (0 == divisor)
    {
        printf("除数不能为0\n");
        return;
    }
    if (dividend * divisor < 0) //表示异号
    {
        while (GetAbsoluteValue(dividend) >= GetAbsoluteValue(divisor))
        {
            dividend += divisor;
            quotient--;
        }
    }
    else
    {
        while (GetAbsoluteValue(dividend) >= GetAbsoluteValue(divisor))
        {
            dividend -= divisor;
            quotient++;
        }
    }

    remainder = dividend;
    printf("商=%d\n", quotient);
    printf("余数=%d\n", remainder);
}

int main()
{
    double Radius;
    const double Pi = 3.1415926;
    int dividend;
    int divisor;
    double sqrtnum;

    printf("-----------------------------------必做作业1：----------------------------------\n");
    printf("-7%%2=%d\n", (-7) % 2);
    printf("7%%-2=%d\n", 7 % (-2));

    printf("\n");
    printf("-----------------------------------必做作业2：----------------------------------\n");
    printf("输入圆的半径: ");
    scanf_s("%lf", &Radius);
    printf("圆的面积=%.6lf\n", Pi * Radius * Radius);

    printf("\n");
    printf("-----------------------------------选做作业1：----------------------------------\n");
    printf("输入被除数: ");
    scanf_s("%d", &dividend);
    printf("输入被除数: ");
    scanf_s("%d", &divisor);
    CalculateQuotientAndReminder(dividend, divisor);

    printf("\n");
    printf("-----------------------------------选做作业2：----------------------------------\n");
    printf("输入被开平方根的数: ");
    scanf_s("%lf", &sqrtnum);
    printf("开根结果=%.10lf\n", GetSqrt(sqrtnum));

    return 0;
}

输出结果：