Q2

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>

 double gt (int n)
{
    double giaithua = 1;

    for( int i = 1; i <= n; i++)
    {
        giaithua=giaithua*i;
    }
  return giaithua;

}

double fa(double x, double c)
 {// write statements from here to compelete the function
	double s = 0,t;
	int i;
	while(1)
	{ t = pow(x,2*i) / gt(2*i);
	  if(t <= c) break;
      s = s + pow(-1,i)*t ;
      i++;
	}
    return(s); //This statement must be changed
 }

//note: int &n means that the variable n is passed to the function, not it's copy.

int findMax (int a[],int n)
{  int max=a[0];
   int i,imax;
   for ( i = 1 ; i < n; i++)
    if(a[i]> max) {max = a[i];imax=i;}
    return imax;
}

int findMin (int a[],int n)
{  int min=a[0];
   int i,imin;
   for ( int i = 1 ; i < n; i++)
    if(a[i]< min){ min = a[i]; imin=i;}
    return imin;
}
void swap ( int &x, int &y)
{ int temp = x;
      x = y;
      y = temp;
}

void removeAt( int i , int a[], int &n)
{ for( int j = i ; j< n-1 ; j++)
         a[j] = a[j+1];
   n--;
}

void fb(int a[], int &n)
 {// write statements from here to compelete the function
 	int imax,imin;

	if(n % 2 !=0 ) {removeAt(0,a,n);removeAt(0,a,n);}
    else { imax = findMax(a,n);
	       imin = findMin(a,n) ;
	       swap(a[imax],a[imin]);}
 }
 //---------------------------------------------
void removeAt (int i , char a[][50] , int &n)
{  for( int j = i; j <n-1; j++) strcpy(a[j],a[j+1]);
   n--;
}

void split ( char s[] , char t[][50] , int &n)
{ int len = strlen(s);
  int i = 0;
 n = 0;
  while(i < len)
  { while ( i < len && s[i] == ' ') i++;
    int k = 0;
    char temp[50];
    while( i < len && s[i] != ' ')
    { temp[k] = s[i];
      k++;
      i++;
    }
    temp[k] ='\0';
    strcpy(t[n], temp);
    n++;

   }
   }


void unSplit( char t[][50],int n, char s[] )
{
	int k = 0;
for ( int i =0 ; i < n; i++)
{  int len = strlen(t[i]);
   for(int j =0 ; j < len; j++)
    { s[k] = t[i][j] ;
       k++;
    }
  s[k] = ' ' ;k++;

 }
 s[k-1] = '\0';
}

void removeLongest(char s[])
{   char t[20][50];
    int n,len=0;
    split(s,t,n);
    int imax = 0;
    // find imax
    for(int i=0;i<n;i++)if(len<strlen(t[i])){ imax=i; len=strlen(t[i]);
                                            }
    removeAt(imax,t,n);
    unSplit(t,n,s);
}
//here
void fc(char s[])
 {// write statements from here to compelete the function

removeLongest(s);

 }
//and here
void fd(char s[])
 {// write statements from here to compelete the function
char t[20][50];
int n;
split(s,t,n);
for(int i=1;i<n;i++)
    removeAt (i,t,n);
unSplit(t,n,s);

 }

//-------------------------------------------------------
void display(int a[], int n) // do not edit this function
 {for(int i=0;i<n;i++) printf("%d ",a[i]);
  printf("\n");
 }

int main()
 {system("cls");
  int choice, i;
  int a[50]; int n;
  int b[] = {3,7,4,2,6}; // n = 5;
  int c[] = {3,9,4,9,2,6}; // n = 6;
  char s[100];
  while(1)
   {printf("\nTEST Q2 (2+2+1+1 = 6 marks):\n");
    printf("1. Test fa()\n");
    printf("2. Test fb()\n");
    printf("3. Test fc()\n");
    printf("4. Test fd()\n");
    printf("0. Exit\n");

    printf("Enter your option (0 -> 4): ");
    scanf("%d",&choice);
    if(choice==0) return(0);
    //=====================================

    switch(choice)
     {case 1: printf("Test fa():\n");
              printf("fa(1.5,0.00001) = %.4f\n",fa(1.5,0.00001));
              break;

      case 2: printf("Test fb():\n");
              n = 5;
              printf("n is odd:\n");
              memcpy(a,b,n*sizeof(int));
              display(a,n);
              fb(a,n);
              display(a,n);
              n = 6;
              printf("n is even:\n");
              memcpy(a,c,n*sizeof(int));
              display(a,n);
              fb(a,n);
              display(a,n);
              break;

      case 3: printf("Test fc():\n");
              strcpy(s,"The quick brown fox");
              printf("%s\n",s);
              fc(s);
              printf("%s\n",s);
              break;

      case 4: printf("Test fd():\n");
              strcpy(s,"A09 A01 A08 A07");
              printf("%s\n",s);
              fd(s);
              printf("%s\n",s);
              break;

      default:printf("Your selection is incorrect\n");
	      break;

     }
   }
  printf("\n");
  system ("pause");
  return(0);
 }