The document contains code for several C++ programs that use functions to calculate factorials, sums of even and odd numbers, solutions to quadratic equations, averages, and combinations. Functions are implemented using for, while, do-while loops. Output examples are provided for sample inputs and calculations for each program.

1. NAME: WAN MOHAMAD FARHAN BIN AB RAHMAN
SJEM2231 STRUCTURED PROGRAMMING
TUTORIAL 4/ LAB 4 (27th OCTOBER 2014)
QUESTION 1
Write a function program to find the factorial of a given number (N!)
//Using for loop:
#include <iostream>
using namespace std;
// Function definition (header and body)
int factorial(int N)
{
int a, factorial=1;
for(a=1; a<=N; a++)
{
factorial = factorial*a;
}
return factorial; // This value is returned to caller
}
int main()
{
int N;
cout << "Please enter a number = ";
cin >> N;
cout << "The factorial for " << N << " is " << factorial(N) << endl;
return 0;
}
//Output for for loop:
Please enter a number = 6
The factorial for 6 is 720

2. //Using if else statement
#include <iostream>
using namespace std;
long factorial ( int a )
{
if (a>1)
return (a*factorial(a-1));
else
return 1 ;
}
int main ()
{
long number;
cout << "Please insert a number : ";
cin >> number;
cout << number <<"! =" << factorial(number)<<endl;
return 0;
}
//Output of if-else statement
Please insert a number : 8
8! =40320

3. // Using the first way of while loop:
#include <iostream>
using namespace std;
// Function definition (header and body)
int factorial(int N)
{
int factorial=1;
while ( N > 0)
/* while loop continues until test condition N>0 is true */
{
factorial= factorial*N;
--N;
}
return factorial; // This value is returned to caller
}
int main()
{
int N;
cout << "Please enter a number = ";
cin >> N;
cout << "The factorial for " << N << " is " << factorial(N) << endl;
return 0;
}

4. //Output of first way of using while loop:
Please enter a number = 8
The factorial for 8 is 40320
//Using the second way of while loop:
#include <iostream>
using namespace std;
// Function definition (header and body)
int factorial(int N)
{
int n=1,factorial=1;
while ( n <= N)
/* while loop continues until test condition N>0 is true */
{
factorial= factorial*n;
n++;
}
return factorial; // This value is returned to caller
}
int main()
{
int N;
cout << "Please enter a number = ";
cin >> N;
cout << "The factorial for " << N << " is " << factorial(N) << endl;

5. return 0;
}
//Output using second way of while loop
Please enter a number = 8
The factorial for 8 is 40320
QUESTION2
Using function program ODD() and EVEN(), find the sum of odd (1+3+ ... +N) and even (2+4+6+…+N) numbers less than N
//Using for loop
#include <iostream>
using namespace std;
// Function definition (header and body)
int sum_even(int N)
{
int i, sum_even=0;
for(i=1; i<N; i++)
{
if(i%2==0)
sum_even=sum_even +i;
}
return sum_even;
}
int sum_odd(int N)
{
int i,sum_odd=0;
for(i=1; i<N; i++)
{
if(i%2!=0)
sum_odd = sum_odd +i;
}

6. return sum_odd;
}
int main()
{
int N;
cout<<"Please enter a number N: ";
cin>>N;
cout<<"nThe summation of even number of N is: " <<sum_even(N) <<endl;
cout<<"The summation of odd number of N is: " <<sum_odd(N) <<endl;
return 0;
}
//Output by using for loop:
Please enter a number N: 10
The summation of even number of N is: 20
The summation of odd number of N is: 25
//Using while loop
#include <iostream>
using namespace std;
// Function definition (header and body)
int sum_even(int N)
{
int i=1, sum_even=0;
while (i< N)

7. {
if (i%2 ==0)
sum_even = sum_even + i;
i++;
}
return sum_even;
}
int sum_odd(int N)
{
int i=1,sum_odd=0;
while (i< N)
{
if (i%2 !=0)
sum_odd = sum_odd + i;
i++;
}
return sum_odd;
}
int main()
{
int N;
cout<<"Please enter a number N: ";
cin>>N;
cout<<"nThe summation of even number of N is: " <<sum_even(N) <<endl;
cout<<"The summation of odd number of N is: " <<sum_odd(N) <<endl;

8. return 0;
}
//Output for while loop
Please enter a number N: 8
The summation of even number of N is: 12
The summation of odd number of N is: 16
//Using do while loop:
#include <iostream>
using namespace std;
/* Function definition (header and body) */
int sum_even(int N)
{
int i=1, sum_even=0;
do
{
if (i%2 ==0)
sum_even = sum_even + i;
i++;
} while (i< N);
return sum_even;
}
int sum_odd(int N)
{
int i=1,sum_odd=0;
do

9. {
if (i%2 !=0)
sum_odd = sum_odd + i;
i++;
} while (i< N);
return sum_odd;
}
int main()
{
int N;
cout<<"Please enter a number N: ";
cin>>N;
cout<<"nThe summation of even number of N is: " <<sum_even(N) <<endl;
cout<<"The summation of odd number of N is: " <<sum_odd(N) <<endl;
return 0;
}
//Output for do while loop
Please enter a number N: 8
The summation of even number of N is: 12
The summation of odd number of N is: 16

10. QUESTION 3
Write a function program to solve the quadratic equations of the form ax2 + bx + c = 0, where a, b, and c are given real number and x is the unknown.
#include <iostream>
#include <cmath>
using namespace std;
/**function prototype or declaration, when int main() is placed on the top**/
float discriminant(float a, float b, float c);
void TWOREAL(float a,float b,float c);
void ONEREAL(float a,float b,float c); //also called as two equal solution
void COMPLEX(float a,float b,float c);
int main()
{
float a, b, c;
cout << "This program is used to solve Quadratic Equationn";
cout << "in the form of ax^2 + bx +cnn";
do
{
cout << "Enter value a:";
cin >> a;
}
while (a == 0); // this is a condition where value of a cannot equal to 0
cout << "Enter value b:";
cin >> b;
cout << "Enter value c:";

11. cin >> c;
if (discriminant(a,b,c) > 0)
TWOREAL(a,b,c);
else if (discriminant(a,b,c) == 0)
ONEREAL(a,b,c);
else
COMPLEX(a,b,c);
return 0;
}
float discriminant(float a, float b, float c)
{
float d = b*b-4*a*c;
return d;
}
void TWOREAL(float a,float b,float c)
{
float x1,x2;
x1 = (-b + sqrtf(discriminant(a,b,c)) )/(2*a);
x2 = (-b - sqrtf(discriminant(a,b,c)) )/(2*a);
cout << "nThe DISCRIMINANT is " << discriminant(a,b,c) << endl;
cout << "It has TWO REAL solution which are " << x1 << " , " << x2 << endl;
}

12. void ONEREAL(float a,float b,float c) // or we can call it as two equal solution
{
float x1;
x1 = -b/(2*a);
cout << "nThe DISCRIMINANT is " << discriminant(a,b,c) << endl;
cout << "It has ONE REAL solution which is " << x1 << endl;
}
void COMPLEX(float a,float b,float c)
{
float x1,x2;
x1 = -b/(2*a);
x2 = sqrtf(-discriminant(a,b,c))/(2*a);
cout << "nThe DISCRIMINANT is " << discriminant(a,b,c) << endl;
cout << "It has TWO COMPLEX solutions which are ";
cout << x1 << "+" << x2 << "i , "<< x1 << -x2 << "i" << endl;
}
// Output for Question 3:
Output1 :
This program is used to solve Quadratic Equation
in the form of ax^2 + bx +c
Enter value a:1
Enter value b:6

13. Enter value c:8
The DISCRIMINANT is 4
It has TWO REAL solution which are -2 , -4
Output2 :
This program is used to solve Quadratic Equation
in the form of ax^2 + bx +c
Enter value a:2
Enter value b:3
Enter value c:4
The DISCRIMINANT is -23
It has TWO COMPLEX solutions which are -0.75+1.19896i , -0.75-1.19896i
Output 3:
This program is used to solve Quadratic Equation
in the form of ax^2 + bx +c
Enter value a:1
Enter value b:8
Enter value c:16
The DISCRIMINANT is 0
It has ONE REAL solution which is -4
QUESTION 4
Write a function program to find the mean (average) of N numbers.
/*The programming codes below are to calculate summation of(1+2+3…N)*/
//Using for loop:
#include <iostream>
using namespace std;
float average(int N)

14. {
int a,b,sum=0;
float result;
for ( a=1;a<=N;a++)
{
cout << “ Value “ << a << “ is: “ ;
cin >> b;
sum=sum+b;
result=float (sum)/N;
}
return (result);
}
int main ()
{
int N;
cout << "Please insert a value,N : ";
cin >> N;
cout << "The average of N values is " << average(N) << endl;
return 0;
}
//Output for for loop :
Please insert a value,N : 5
Value 1 is:10
Value 2 is:3
Value 3 is:7
Value 4 is:2
Value 5 is:114
The average of N values is 27.2
//Using while loop
#include <iostream>
using namespace std;
float average(int N)

15. {
int a=1,b, sum=0;
float result;
while(a<=N)
{
cout << "Value " << a << " is: " ;
cin >> b;
sum= sum + b ;
a++;
result=float (sum)/N;
}
return (result);
}
int main ()
{
int N;
cout << "Please insert a value N : ";
cin >> N;
cout << "The average of N values is " << average(N) << endl;
return 0;
} //Output for while loop:
Please insert a value,N : 5
Value 1 is:10
Value 2 is:3
Value 3 is:7
Value 4 is:2
Value 5 is:114
The average of N values is 27.2

16. //Using do while loop
#include <iostream>
using namespace std;
float average(int N)
{
int a=1, b, sum=0;
float result;
do
{
cout << "Value " << a << " is: " ;
cin >> b;
sum= sum + b ;
a++;
result=float (sum)/N;
} while(a<=N) ;
return (result);
}
int main ()
{
int N;
cout << "Please insert a value N : ";
cin >> N;
cout << "The average of N values is " << average(N) << endl;
return 0;
}

17. //Output for do while loop
Please insert a value,N : 5
Value 1 is:10
Value 2 is:3
Value 3 is:7
Value 4 is:2
Value 5 is:114
The average of N values is 27.2
QUESTION 5
Using the function program, calculate the formula C(n,k )= ( )
#include <iostream>
using namespace std;
/*** function prototype or declaration***/
int fact(int n);
void COMB(int n,int k);
int main ()
{
int n,k;
cout << "This program is used to calculate C(n,k)." << endl;
do
{
cout << "Value of n should be larger than k, n>k" << endl;
cout << "Enter positive integer n:";
cin >> n;
cout << "Enter positive integer k:";
cin >> k;
}

18. while (n < 0 || k<0 || n<k);
COMB(n,k);
return 0;
}
int factorial(int n)
{
int fact = 1;
if (n == 0)
return 1;
else
{
for (int i = 1; i <= n; i++)
fact = fact * i;
return fact;
}
}
void COMB(int n,int k)
{
int comb = factorial(n)/(factorial(k)*factorial(n-k));
cout << "C(" << n << "," << k << ")= " << comb << endl;
}
//Output for Question 5:
This program is used to calculate C(n,k).
Value of n should be larger than k, n>k
Enter positive integer n:5

19. Enter positive integer k:7
Value of n should be larger than k, n>k
Enter positive integer n:-4
Enter positive integer k:-7
Value of n should be larger than k, n>k
Enter positive integer n:3
Enter positive integer k:2
C(3,2)= 3