C primer plus第6版第5章プログラミング練習解答

//      ，                       
//  #define const      60      const  
//  while          ，           0       

#include 

int main(void)
{
	const int CHANGENUM = 60;
	int time, hours, minutes; //time:      hours:       minutes：     
	printf("     (      )： ");
	scanf("%d", &time); 

	while (time > 0)
	{
		hours = time / CHANGENUM;
		minutes = time % CHANGENUM;
		printf("%d   %d  %d  
", time, hours, minutes);
		printf("       (      ): ");
		scanf("%d", &time);
	}
	printf("    ！");
			
	return 0;

/*      ，          ，          
  10     。              、     */

#include 

int main(void)
{
	int num;

	printf("Please enter a number: ");
	scanf("%d", &num);

	for (int i = 0; i < 10; ++i)
		printf("%d\t", ++num);

	return 0;

}

//        
//          
//while
#include 

int main(void)
{
	int days; //     
	int week, day; //         

	printf("Please enter the days number.(enter a number < 0 to quit): ");
	scanf("%d", &days);

	while (days > 0)
	{
		week = days / 7;
		day = days % 7;
		printf("%d days are %d weeks, %d days.
", days, week, day);
		printf("Please enter the days number again.(enter a number < 0 to quit):");
		scanf("%d", &days);
	}
	
	printf("Job Done!");

	return 0;
}

//      ，          （cm），
//               ，       
//            ，           

#include 
#define CMTOFEET 0.032808 //1  =0.032808  feet
#define CMTOINCH 0.3937008 //1  =0.3937008  feet
#define FEETOINCH 12 //1  feet = 12   inch

int main(void)
{
	float height; //    
	int feet; //    
	float inch; //    

	printf("Please enter your height in cm: ");
	scanf("%f", &height);

	while (height > 0)
	{
		feet = height * CMTOFEET;
		inch = (height * CMTOINCH) - (FEETOINCH*feet);
		printf("%.1f cm = %d feet, %.1f inches
", height, feet, inch);
		printf("Enter a height in centimeters (<=0 to quit): ");
		scanf("%f", &height);
	}

	printf("Job Done!");

	return 0;
}

/*  n         ， n  $n*/

#include 

int main(void) //
{
	int count, sum;
	//count = 0;
	//sum = 0;
	int n;

	printf("Please enter the day: ");
	scanf("%d", &n);
	
	while (n > 0)
	{
		count = 0;
		sum = 0;
		while (count++ < n)
			sum = sum + count;
		printf("sum = %d
", sum);
		printf("Please enter the day again(enter <=0 to quit:");
		scanf("%d", &n);
	}

	printf("Job Down!");

	return 0;
}

/*  n         ， n  $n*/
//    n  $n*n

#include 

int main(void) //
{
	int count, sum;
	//count = 0;
	//sum = 0;
	int n;

	printf("Please enter the day: ");
	scanf("%d", &n);

	while (n > 0)
	{
		count = 0;
		sum = 0;
		while (count++ < n)
			sum = sum + count * count;
		printf("sum = %d
", sum);
		printf("Please enter the day again(enter <=0 to quit:");
		scanf("%d", &n);
	}

	printf("Job Down!");

	return 0;
}

//        double    ，         
//          

#include 

double cube(double a);//    

int main(void)
{
	double num;
	printf("Please enter a number: ");
	scanf("%lf", &num);

	double cube_num = cube(num);
	printf("The cube of %.2lf is %.2lf.", num, cube_num);

	return 0;
}

double cube(double a)
{
	return a * a * a; //    
}

//         ，                        
//      ，               。
//      ，    

#include 

int main(void)
{
	int one, two, moduli;

	printf("This program computers moduli.
");
	printf("Enter an integer to serve as the second operand: ");
	scanf("%d", &two);
	printf("Now enter the first operand: ");
	scanf("%d", &one);

	while (one > 0)
	{
		moduli = one % two;
		printf("%d %% %d is %d.
", one, two, moduli);
		printf("Enter next number for first operand (<= 0 to quit): ");
		scanf("%d", &one);
	}

	printf("Job Done!");

	return 0;
}

//        ，  double       ，              
//             ，         

#include 	

void Temperatures(double a);

int main(void) 
{
	double ft; //    
	printf("Please enter a temperature number(  ): ");

	while (scanf("%lf", &ft) == 1)
	{
		Temperatures(ft);
		printf("Please enter the next number: ( q to quit ) : ");
	}

	printf("Job Done!");

	return 0;
}

void Temperatures(double a)
{
	double ct; //    
	double kt; //    
	ct = 5.0 / 9.0 * (a - 32.0);
	kt = ct + 273.16;
	printf("%.2f     = %.2f      = %.2f     
", a, ct, kt);
}