How do you write a C plus plus program to display the Fibonacci sequence to 10 terms and then display the 20th term?

Answer 1

#include<iostream>

#include<vector>

#include<cassert>

using namespace std;

// Returns a vector of Fibonacci numbers from start to max.

// Sequence A000045 in OEIS if start is 0.

vector<unsigned> fibonacci (const unsigned start, const unsigned max)

{

// Invariants:

if (1<start)

throw std::range_error

("vector<unsigned> fibonacci (const unsigned start, const unsigned max): start < 1");

if (max<start)

throw std::range_error

("vector<unsigned> fibonacci (const unsigned start, const unsigned max): max < start");

// Empty set...

vector<unsigned> fib {};

if (max)

{

// First term...

fib.push_back (start);

if (1<max)

{

// Second term...

fib.push_back (1);

// All remaining terms...

unsigned next = 0;

while ((next = fib.back()+fib[fib.size()-2]) <= max)

fib.push_back (next);

}

}

return fib;

};

// Return true if the given number is prime.

bool is_prime (const unsigned num)

{

if (num<2) return false;

if (!(num%2)) return num==2;

for (unsigned div=3; div<=sqrt(num); div+=2)

if (!(num%div)) return false;

return true;

}

// Displays all prime Fibonacci numbers in range [1:10,000].

int main()

{

const unsigned max=10000;

vector<unsigned> f = fibonacci (1, max);

cout << "Prime Fibonacci numbers in range [1:" << max << "]\n";

for (auto n : f)

if (is_prime (n))

cout << n << ", ";

cout << "\b\b " << endl; // backspace and overwrite trailing comma

}

Answer 2

#include<iostream>

#include<vector>

#include<cassert>

using namespace std;

// Returns a vector of Fibonacci numbers from 0 to the nth term.

// Sequence A000045 in OEIS.

vector<unsigned> fibonacci (const unsigned terms)

{

// Empty set...

vector<unsigned> fib {};

if (terms)

{

// First term...

fib.push_back (0);

if (1<terms)

{

// Second term...

fib.push_back (1);

// All remaining terms (2 to n-1).

for (unsigned term=2; term<terms; ++term)

fib.push_back (fib[term-2]+fib[term-1]);

}

}

return fib;

};

// Displays Fibonacci sequence to 10 terms followed by the 20th term.

int main()

{

const unsigned max=20;

vector<unsigned> f = fibonacci (max);

assert (f.size()==max);

cout << "Fibonacci Sequence\n10 terms: ";

for (unsigned n=0; n<10; ++n)

cout << f[n] << ", ";

cout << "\b\b "; // backspace and overwrite trailing comma

cout << "\n20th term: " << f[max-1] << std::endl;

}

Answer 3

You can use a loop statement to input the numbers. Here is a code snippet:

int i, arr[10];

cout<<"Enter the 10 numbers: ";

for( i=0; i<10; i++)

cin>>arr[i];//Inserting the elements in the array