Primer C 4th(第5章习题)

 5-1

#include <stdio.h>
#include <stdlib.h>

#define H2M 60

float Hour2Min(float mins)
{
 float hours;

 if(mins > 0)
 {
  hours = mins / H2M;
 }
 else
 {
  return 0; 
 }

 return hours;
}

int main(void)
{
 float minutes;
 float hours;

 while(1)
 {
  printf("Please enter how many minutes:");

  scanf("%f", &minutes);

  printf("%f mins \n", minutes);

  if((hours=Hour2Min(minutes)) == 0)
  {
   exit(0);
  }
  
  printf("It's about %f hours. \n", hours);
 }

 return 0;
}

==================================================================

5-2

#include <stdio.h>

#define NUM 10

int main(void)
{
 int a;
 int num;

 while(1)
 {
  printf("Please enter an integral:");
  scanf("%d", &a);

  num = NUM;
  while(num-- >= 0)
  {
   printf("%d ", a++);
  }

  printf("\n");
 }

 return 0;
}

==================================================================

5-3

#include <stdio.h>

int main(void)
{
 int count, sum;
 int num;

 printf("Enter number of integrals:");
 scanf("%d", &num);
 count = 0;
 sum = 0;
 while(count++ < num)
  sum = sum + count;
 printf("sum = %d\n", sum);

 return 0;
}

==================================================================

5-4

#include <stdio.h>

int main(void)
{
 int count, sum;
 int num;

 printf("Enter number of integrals:");
 scanf("%d", &num);
 count = 0;
 sum = 0;
 while(count++ < num)
  sum = sum + count;
 printf("sum = %d\n", sum);

 return 0;
}

==================================================================

5-5

#include <stdio.h>

int main(void)
{
 int count, sum;
 int num;

 printf("Enter number of integrals:");
 scanf("%d", &num);
 count = 0;
 sum = 0;
 while(count++ < num)
  sum = sum + count*count;
 printf("sum = %d\n", sum);

 return 0;
}

==================================================================

5-6

#include <stdio.h>

float Cube(float a)
{
 float cube;

 cube = a*a*a;

 return cube;
}

int main(void)
{
 float data;

 while(1)
 {
  printf("Please enter a data:");
  scanf("%f", &data);

  printf("%f Cube is %f. \n", data, Cube(data));
 }

 return 0;
}

==================================================================

5-7

#include <stdio.h>

void Temperatures(double fahr)
{
 double celsius;
 double kelvin;

 celsius = 1.8*fahr + 32.0;
 kelvin = celsius + 273.16;

 printf("celsius is %f.\n", celsius);
 printf("kelvin is %f.\n", kelvin);
}

int main(void)
{
 double fahrenheit;

 printf("Please enter fahrenheit:");
 scanf("%f", &fahrenheit);

 printf("fahrenheit is %f.\n", fahrenheit);

 Temperatures(fahrenheit);

 return 0;
}