C Primer Plus 5

一、运算符、表达式和语句

1、编程练习

（1）编写一条程序，把用分钟表示的时间换成用小时和分钟表示的时间。使用#define或者const创建一个表示60的符号常量或者const常量。通过while循环让用户重复输入值，直到小于等于0才停止循环。

#include<stdio.h>
#include<windows.h>
#define MIN_PER_HOU 60    //每小时有60min
int main(void)
{
    int hours,minutes,input;
    printf("Convert minutes to hours!\n");
    printf("Please input the number of minutes:\n");
    scanf("%d",&input);
    while(input>0)
    {
        hours = input/MIN_PER_HOU;
        minutes = input%MIN_PER_HOU;
        printf("Convert to %d hours and %d minutes!",hours,minutes);
        printf("Please continue input the number of minutes:\n");
        scanf("%d",&input);
    }
    printf("Program exit!\n");
    system("pause");
    return 0;    
}

(2)编写一个程序，提示用户输入一个整数，然后打印从该数到比该数大10的所有整数，打印各值之间用一个空格分开。

#include<stdio.h>
#include<windows.h>
int main(void)
{
    int counter,i=0;
    printf("Please input the number:\n");
    scanf("%d",&counter);
    while(i<=10)
    {
        printf("%d\n",counter);
        counter++;
        i++;
    }
    system("pause");
    return 0;
}

(3)编写一个程序，将天数转化为周数和天数

#include<stdio.h>
#include<windows.h>
#define WEEKS_PER_DAY 7
int main(void)
{
    int days,weeks,input;
    printf("Let's convert days to weeks!\n");
    printf("Please input the days:\n");
    scanf("%d",&input);
    while(input>0)
    {
        weeks = input/WEEKS_PER_DAY;
        days = input%WEEKS_PER_DAY;
        printf("%d days is equal to %d weeks and %d days!\n",input,weeks,days);
        printf("If you want to go on,please input another number:\n");
        scanf("%d",&input);
    }
    while(input<=0)
    {
        printf("Thanks to join the program!\n");
        break;
    }
    system("pause");
    return 0;
}

(4)编写一个程序，使用户输入一个double类型的数，并打印立方值。

#include<stdio.h>
#include<windows.h>
double cubic(double n);
int main(void)
{
    double input;
    printf("Enter the double datum to calc cubic:\n");
    scanf("%lf",&input);
    cubic(input);
    printf("program exit!\n");
    system("pause");
    return 0;
}
double cubic(double n)
{
    double t = n *n *n;
    printf("The %lg's cubic is %lg!\n",n,t);
    return t;
}

(5) 编写一个程序，自定义函数temperatures()，输入华氏温度，计算摄氏温度和开氏温度。并以小数点后两位精度显示三种温度。

#include<stdio.h>
#include<windows.h>
int Temperatures(double fah);
int main(void)
{
    double input;
    printf("This program convert fah to cel and kel.\n");
    printf("Enter a fah to start:\n");
    while(scanf("%lf",&input)==1)
    {
        Temperatures(input);
        printf("Enter the next fah(q to quit):\n");
    }
    printf("Done!\n");
    system("pause");
    return 0;
}
int Temperatures(double fah)
{
    const double F_TO_C = 32.0;
    const double C_TO_K = 273.16;
    double cel,kel;
    cel = 5.0/9.0*(fah-F_TO_C);
    kel = cel + C_TO_K;
    printf("%.2f.fah,equal %.2f celsius,and %.2f kel\n",fah,cel,kel);
    return 0; 
}