Question

// HOMEWORK
// add methods to find the area and circumference of a circle
// add a method to find factorial of a long int that returns long
// this is Kelvin Lam solution to the above homework
public
static double areaOfCirc(double rad){
return Math.PI * rad * rad;
}
public
static double circOfCirc(double rad){
return 2 * Math.PI * rad;
}
public
static long factorial(long n){
// precondition: n is supplied by the user
// postcondition: the factorial of n is calculated iteratively and returned
long f=1;
for (;n>0;n--)
f*=n;
return f;
}
// recursive implementation of factori

Answer 1

// recursive implementation of factorial method
public
static long fact(long n){
// precondition: n is supplied by the user
// postcondition: the factorial of n is calculated recursively and returned
// base case always comes first
if (n==0)
return 1;
else
return n * fact(n-1); // from the recursive definition
　
}
// add a method to compute the nth prime number and return it
// add a method to generate the first n fibonacci numbers
public
static int nthPrime(int n){
int k;
int pCtr=1;
int p=2;
if (n==1)
return 2;
while (pCtr<n)
{
for ( k=2;k<=Math.sqrt(++p);k++)
if (p%k == 0 ) // the number prime is not a prime if true
break; // exit the inner for loop since prime is not a prime
// why did we exit inner for loop?
if (k>Math.sqrt(p)) // p is a prime
pCtr++;
}
return p;
}
public
static int fib(int n){
//precondition: user supplies n
// postcondition: the first n fib numbers are
// generated recursively one to a line
// base case
if ((n==1)||(n==2))
return 1;
else
return fib(n-1) + fib(n-2);
}
public
static void fibonacci(int n){
//precondition: user supplies n
// postcondition: the first n fib numbers are
// generated iteratively one to a line
int ctr=1;
if (n==1)
System.
out.println("fib"+ctr+":"+ 1);
else
if (n==2){
System.
out.println("fib"+ ctr+":"+ 1);
System.
out.println("fib"+ ++ctr+":"+ 1);
}
else{
int current=1;
int prev=1;
int next;
System.
out.println("fib"+ ctr+":"+ 1);
System.
out.println("fib"+ ++ctr+":"+ 1);
for (;ctr<=n;ctr++)
{next=prev +current;
System.
out.println("fib"+ ++ctr+":"+ next);
prev=current;
current=next;
}
}
}
}

Answer 2

any1 can solve this ?