c how to program 习题 3.18

运行结果：

C语言代码：

/* c how to program 习题 3.18 */
#include <stdio.h>
#include <stdlib.h>

int main()
{
    //定义变量
    double sales, salary, baseSalary = 200, royalty = 0.09;

    //请输入第一个职工销售额
    printf("Enter sales in dollars (-1 to end): ");
    scanf("%lf", &sales);

    while(sales != -1.0){

        //计算工资
        salary = baseSalary + sales * royalty;

        //打印工资
        printf("Salary is: $%.2lf\n\n", salary);

        //请输入下一个职工销售额
        printf("Enter sales in dollars (-1 to end): ");
        scanf("%lf", &sales);
    }

    return 0;
}