Question

c++ fibonacci code using loops

Here are 8 Fibonacci numbers: 1, 1, 2, 3, 5, 8, 13, 21 Note that the first Fibonacci number is 1, F(1) = 1 The second Fibonacci number is 1, i.e. F(2) = 1 Other Fibonacci numbers in the sequence is the sum of two previous Fibonacci numbers. For example F(3) = F(2) + F(1). In general F(n) = F(n-1) + F(n-2) Write a program to do the following tasks. User entries are shown in bold. First print your name in capital letters. 1) Ask user to enter a value for N. Find the sum of first N positive integer numbers. For example for N=3, you add numbers 1+2+3 which results in answer of 6. Part 1: Sum of first N positive integers: Enter N: 3 Sum of first 3 positive integer numbers is 6. 2) Ask user to enter a value for N. Print first N numbers in Fibonacci sequence. For example for N = 4, you generate the following output: Part 2: Print first N Fibonacci numbers, their sum and average: Enter N: 4 First 4 Fibonacci numbers are: F(1) = 1 F(2) = 1 F(3) = 2 F(4) = 3 Sum of the first 4 Fibonacci numbers = 7 Average of the first 4 Fibonacci numbers = 1.75 3) Ask user to enter a value for N. Ask user to enter a value for M. You want to calculate first N Fibonacci numbers but output only every Mth term. (Use modulus operator %). For example if N=8 and M=3, then your output should be as follows: Part 3: Generate N Fibonacci numbers but print every M term: Enter N: 8 Enter M: 3 8 Fibonacci numbers printed with sequence number multiple of 3: F(3) = 2 F(6) = 8

Answer 1

#include <iostream>
using namespace std;

int main()
{
int N, M;
int sum = 0;
int fib1, fib2, fib3;
float average;

cout << "JOSEPHINE" << endl;
  
cout << "Part 1: Sum of first N positive integers:" << endl;
cout << "Enter N: " ;
cin >> N;
// For loop is used to vary the value of number from 1 to N
for(int number= 1; number<=N; number++)
{
// Keep adding number to the previous value of sum in every cycle of for loop
sum = sum + number;
}
cout << "Sum of first " << N << " positive integer numbers is " << sum << "." << endl << endl;
  
cout << "Part 2: Print first N Fibonacci numbers, their sum and average:" << endl;
cout << "Enter N: " ;
cin >> N;
// Assign the first two numbers of Fibonacci series in fib1 and fib2
fib1 = 1;
fib2 = 1;
// add the first two numbers to get the sum
sum = fib1 + fib2;
// print the first two numbers
cout << "First " << N << " Fibonacci numbers are:" << endl;
cout << "F(1) = " << fib1 << endl;
cout << "F(2) = " << fib2 << endl;
// for loop is used to generate fibonacci series from third term as
// first two terms are printed out of loop
for(int i= 3; i<=N; i++)
{
// Generate every third term by adding previous two terms and display
fib3 = fib1 + fib2;
cout << "F(" << i << ") = " << fib3 << endl;
// add the generated third term to sum
sum = sum + fib3;
// assign the third term to fib2 and second term to fib1
fib1 = fib2;
fib2 = fib3;
}
// find the average and print the sum and average
average = ((float)sum/N);
cout << "Sum of the first " << N << " Fibonacci numbers = " << sum << endl;
cout << "Average of the first " << N << " Fibonacci numbers = " << average << endl << endl;
  
  cout << "Part 3: Generate N Fibonacci numbers but print every M term:" << endl;
cout << "Enter N: " ;
cin >> N;
cout << "Enter M: " ;
cin >> M;
cout << N << " Fibonacci numbers printed with sequence number multiple of " << M << ":" << endl;
fib1 = 1;
fib2 = 1;
// print the first two numbers if term is 1
if(M == 1)
{
cout << "F(1) = " << fib1 << endl;
cout << "F(2) = " << fib2 << endl;
}
// print the second number if term is 2
else if(M == 2)
{
cout << "F(2) = " << fib2 << endl;
}
for(int i= 3; i<=N; i++)
{
fib3 = fib1 + fib2;
// check if i is divisible by M. If so, print the i(th) terms
if(i%M == 0)
cout << "F(" << i << ") = " << fib3 << endl;
fib1 = fib2;
fib2 = fib3;
}
return 0;
}
=====================================================================================

#include <iostream> using namespace std; int main() { int N, M; int sum = 0; int fibi, fib2, fib3; float average; cout << "JOSEPHINE" << endl; cout << "Part 1: Sum of first N positive integers: " << endl; cout << "Enter N: "; cin >> N; // For Loop is used to vary the value of number from 1 to N for(int number= 1; number<=N; number++) // Keep adding number to the previous value of sum in every cycle of for Loop sum = sum + number; cout << "Sum of first " << N << " positive integer numbers is " << sum << "." << endl << endl; cout << "Part 2: Print first N Fibonacci numbers, their sum and average:" << endl; cout << "Enter N: "; cin >> N; // Assign the first two numbers of Fibonacci series in fibi and fib2 fib1 = 1; fib2 = 1;

// add the first two numbers to get the sum sum = fib1 + fib2; // print the first two numbers cout << "First " << N << " Fibonacci numbers are:" << endl; cout << "F(1) = " << fibi << endl; cout << "F(2) = " << fib2 << endl; Il for Loop is used to generate fibonacci series from third term as // first two terms are printed out of Loop for(int i= 3; i<=N; i++) // Generate every third term by adding previous two terms and display fib3 = fibi + fib2; cout << "F" << i << ") = " << fib3 << endl; // add the generated third term to sum sum = sum + fib3; // assign the third term to fib2 and second term to fibi fib1 = fib2; fib2 = fib3; Il find the average and print the sum and average average = ((float)sum/N); cout << "Sum of the first " << N << "_Fibonacci numbers = " << sum << endl; cout << "Average of the first " << N << " Fibonacci numbers = " << average << endl << endl; cout << "Part 3: Generate N Fibonacci numbers but print every M term:" << endl; cout << "Enter N: "; cin >> N;

<< ":" << endl; cin >> M; cout <<N << " Fibonacci numbers printed with sequence number multiple of " << M fib1 = 1; fib2 = 1; // print the first two numbers if term is 1 if(M == 1) cout << "F(1) = " << fibi << endl; cout << "F(2) = " << fib2 << endl; // print the second number if term is 2 else if(M == 2) cout << "F(2) = " << fib2 << endl; for(int i= 3; i<=N; i++) fib3 = fibi + fib2; // check if i is divisible by M. If so, print the i(th) terms if(i M == 0) cout << "F" << i << ") = " << fib3 << endl; fib1 = fib2; fib2 = fib3; return 0;

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

Sample output:

JOSEPHINE Part 1: Sum of first N positive integers: Enter N: 3 Sum of first 3 positive integer numbers is 6. Part 2: Print first N Fibonacci numbers, their sum and average: Enter N: 4 First 4 Fibonacci numbers are: F(1) = 1 F(2) = 1 F(3) = 2 F(4) = 3 Sum of the first 4 Fibonacci numbers = 7 Average of the first 4 Fibonacci numbers = 1.75 Part 3: Generate N Fibonacci numbers but print every M term: Enter N: 8 Enter M: 3 8 Fibonacci numbers printed with sequence number multiple of 3: F(3) = 2 F(6) = 8