แบบฝึกหัดบทที่ 9 : ฟังก์ชัน

ข้อ 1 (page 23)

#include<stdio.h>
#include<conio.h>
#include<math.h>
float n2=2;
float power(float n1,float n2)
{
      float c;
      c=pow(n1,n2);
      return(c);
}
float sqroot(float n1)
{
      float a;
      a=sqrt(n1);
      return(a);
}
main()
{
      int num2,num3=2;
      float num1,result,ans;
      printf("Enter number : ");
      scanf("%f",&num1);
      printf("Please select choice (1 = power , 2 = square root) : ");
      scanf("%d",&num2);
            if(num2==1)
            {
                      result=power(num1,num3);
                      printf("Result = %.2f",result);
                      getch();
            }
            else
            {
                      if(num2==2)
                      {
                                 result=sqroot(num1);
                                 printf("Result = %.2f",result);
                                 getch();
                      }
                      else
                      {
                                 printf("Menu Error!!!");
                                 getch();
                      }
            }
}


ข้อ 2 (page 27 )

#include<stdio.h>
#include<conio.h>
char cal_grade(float score);
main()
{
      float x;
      char grade;
      printf("Enter score : ");
      scanf("%f",&x);
      grade=cal_grade(x);
      printf("You get %c !!!",grade);
      getch();
}
char cal_grade(float score)
{
      char grade;
      if(80<=score&&score<=100)
      {
            grade='A';
      }
      else
      {
            if(70<=score&&score<=79)
            {
                  grade='B';
            }
            else
            {
                  if(60<=score&&score<=69)
                  {
                        grade='C';
                  }
                  else
                  {
                        if(50<=score&&score<=59)
                        {
                              grade='D';
                        }
                        else
                        {
                              grade='F';
                        }
                  }
            }
      }
      return(grade);
}



ข้อ  3 (page 28)
#include<stdio.h>
#include<conio.h>
float cal_avg(float x,float y);
main()
{
      float a,b,c;
      printf("Enter a : ");
      scanf("%f",&a);
      printf("Enter b : ");
      scanf("%f",&b);
      c=cal_avg(a,b);
      printf("Average is %f",c);
      getch();
}
float cal_avg(float x,float y)
{
      float sum,avg;
      sum=x+y;
      avg=sum/2;
      return(avg);
}


ข้อ 4

#include<stdio.h>
#include<conio.h>
int findmax(int x,int y);
main()
{
      int a,b,c;
      printf("Enter number 1 : ");
      scanf("%d",&a);
      printf("Enter number 2 : ");
      scanf("%d",&b);
      c=findmax(a,b);
      printf("Max is %d",c);
      getch();
}
int findmax(int x,int y)
{
      int i;
      if(x<y)
      {
             i=y;
      }
      else
      {
             i=x;
      }
      return(i);
}