# Finding nth prime number

• 04-12-2010, 10:47 PM
dextr
Finding nth prime number
I am trying to write a code for a program that will find the n th prime number.As for example 7 is the 4th prime number,11 is the 5th.
The method will take argument as n,and it will find the nth prime number.But I am facing some difficulty with the code.The code doesnt terminate by itself and doesnt return the desired value.Someone please help me out.
Code:

```  public class Problem{         /**         * @param args         */         public int findAns(int n){ int count=0; int ret=0; while(count<n){         for(int i=0;i<Integer.MAX_VALUE;i++){                 if(ifPrime(i)){                         count++;                 }                 ret=i;         } } return ret;         }                 public boolean ifPrime(int num){                         boolean b=false;                         int i;                     for (i=2; i < num ;i++ ){                       int n = num%i;                       if (n==0){                         b=false;                         break;                       }                     }                     if(i == num){                       b=true;                     }                     return b;                 }         public static void main(String[] args) {                 // TODO Auto-generated method stub System.out.println(new Problem().findAns(10));         } }```
• 04-12-2010, 10:57 PM
Fubarable
Are you sure that you want both a for loop and a while loop here:
Code:

```    while(count<n){         for(int i=0;i<Integer.MAX_VALUE;i++){                 if(ifPrime(i)){                         count++;                 }                 ret=i;         }     }```