c how to program 习题4.15

运行结果：

C语言代码：

/* c how to program 习题4.15
** 计算利息 */
#include <stdio.h>
#include <math.h>
// function main begins program execution
int main( void )
{
    //定义principal为本金，rate为利率
    double principal = 1000.0;
    int rate;

    //利用循环计算不同利率的利息
    for(rate = 5; rate <= 10; rate++){
        //打印当前利率
        printf("Interest Rate:%lf\n", rate/100.0);

        //打印列表格式
        printf("%4s%21s\n", "Year", "Amount on deposit");

        //利用循环计算1=10的利息
        for(unsigned int year = 1; year <= 10; ++year){
            //计算利息
            double amount = principal * pow(1.0 + rate/100.0, year);
            //按格式输出结果
            printf("%4u%21.2f\n", year, amount);
        }
        //换行
        puts("");
    }
}