Answer to Question #301717 in C++ for gift

Question

1. A prime number is an integer greater than one and divisible only by itself and one.

The first seven prime numbers are 2, 3, 5, 7, 11, 13, and 17. Write a program that displays all the

prime numbers between 1 and 100

2. Write another program that accepts a number from the user and returns th Fibonacci value of that

number. You should use recursion in here.

3. Write a program that accepts a number and determine whether the number is prime or not.

4. Write a C++ code that computes the sum of the following series.

Sum = 1! + 2! + 3! + 4! + …n!

The program should accept the number from the user.

5. Write a C++ code to display only even numbers found between 222 and 180.

6. Write and run a program that reads a positive integer n and then prints a diamond of numbers Use for loop.  

Answer 1

#include<conio.h>
#include<stdio.h>
#include<stdlib.h>
using namespace std;


int IsPrime(int n) 
{
  int i, FlagPrime = 1;
  if (n == 0 || n == 1) FlagPrime=0;
  else 
  {
    for(i = 2; i <= n/2; ++i) 
	{
      if(n % i == 0)  {FlagPrime = 0; break;}
    }
  }
  return (FlagPrime);
}


// calculating factorial of given number n
int fact(int n)
{
    int k = 1;
    for (int i = 2; i <= n; i++)	k *= i;
    return k;
}


int main()
{
/*
1.	A prime number is an integer greater than one and divisible only by itself and one.
	The first seven prime numbers are 2, 3, 5, 7, 11, 13, and 17. Write a program that displays all the
	prime numbers between 1 and 100
*/
	int Sum=0;
	int n=0,m=1,a,b,c,i,j,s;
	cout<<"\nSolution-1";
	while(n<7)
	{
		if(IsPrime(m) ==1) {cout<<"\nPrime No. "<<n+1<<" = "<<m; n++;}
		m++;
	}	


/*
2. 	Write another program that accepts a number from the user and returns th Fibonacci value of that
	number. You should use recursion in here.
*/
	cout<<"\nSolution-2";
	cout<<"\n\nEnter a number: "; cin>>n;
	a=0;	b=1; m=2;
	cout<<"\nFibonacci Term-1 = "<<a;
	cout<<"\nFibonacci Term-2 = "<<b;
	for(m=2;m<=n;m++)
	{
		c=a+b;
		cout<<"\nFibonacci Term-"<<m+2<<"  = "<<c;
		a=b;
		b=c;
	}


/*
3. Write a program that accepts a number and determine whether the number is prime or not.
*/
	cout<<"\nSolution-3";
	cout<<"\n\nEnter a number: "; cin>>n;
	if(IsPrime(m) ==1) 	cout<<"\nThe number "<<n<<" is a PRIME number.";
	else				cout<<"\nThe number "<<n<<" is a NOT a PRIME number.";	


/*
4. Write a C++ code that computes the sum of the following series.
	Sum = 1! + 2! + 3! + 4! + …n!
	The program should accept the number from the user.
*/
	cout<<"\nSolution-4";
	cout<<"\n\nEnter a number: "; cin>>n;
	cout<<"Sum = ";
	for(m=1;m<=n;m++)	
	{
		Sum = Sum + fact(m);
		cout<<"!"<<m<<"+";
	}
	cout<<" = "<<Sum;




/*
5. Write a C++ code to display only even numbers found between 222 and 180.
*/
	cout<<"\nSolution-5";
	cout<<"\nEven Numbers between 222 and 180: ";
	for(n=180;n<=222;n++)
	{
		if(n%2==0) cout<<n<<", ";
	}
/*
	6. Write and run a program that reads a positive integer n and then prints a diamond of numbers Use for loop.  
*/
	cout<<"\nSolution-6";
	cout<<"\n\nEnter a number: "; cin>>n;
    s = n-1;
    for(a=1; a<=n; a++)
    {
        for(b=1; b<=s; b++)	cout<<" ";
        s--;
        for(b=1; b<=(2*a-1); b++)	cout<<"*";
        cout<<endl;
    }
    s = 1;
    for(a=1; a<=(n-1); a++)
    {
        for(b=1; b<=s; b++)	cout<<" ";
        s++;
        for(b=1; b<=(2*(n-a)-1); b
		++)	cout<<"*";
        cout<<endl;
    }
    cout<<endl;
}