# Cracking the coding interview | Step-4

## Question 1:

Number of Prime numbers in specified range.

Write a function to find the count of the number of prime numbers in a specified range. The starting and ending number of the range will be provided as input parameters to the function.
Assumption : 2<= starting number of the range <= ending number of the range <= 7919
Example 1: If the starting and ending number of the range is given as 2 and 20, the method must return 8, because there are 8 prime numbers in the specified range from 2 to 20, namely( 2, 3, 5, 7, 11, 13, 17,19 ).
Example 2: If the starting and ending number of the range is given as 700 and 725, the method must return 3, because there are 3 prime numbers in the specified range from 700 to 725, namely( 701, 709, 719 ).

//Code :

import java.io.*;
import java.util.*;
class UserMainCode{
public int countPrimesInRange(int input1, int input2){

int count=0;
int pcount=0;
for(int i=input1;i<=input2;i++){

count=0;
for(int j=2;j<=Math.sqrt(i);j++) {

if(i%j==0)
count++;
}
if(count==0)
pcount++;
}
return count;
}}

## Question 2:

All Digits Count

Write a function to find the count of ALL digits in a given number N. The number Will be Passed
to the function as an input parameter of type int.
Assumption: The input number will be a positive integer number>=1 and <=250000.
For e.g.
If the given number is 292, the function should return 3 because there are 3 digits in this number
If the given number is 1015, the function should return 4 because there are 4 digits in this number

//Code :

import java.io*;
import java.util.*;
class UserMainCode
{
public int allDigitsCount(int input1)
{
String str=Integer.toString(input1);
return str.length();
}
}

## Question 3:

Unique Digit Count

Write a function to find the count of unique digits in a given number N. The number will be passed to the function as the input parameter of type int.
Assumption: The input number will be a positive integer number>=1 and <= 25000.
For e.g.
If the given number is 292, the function should return 2 because there are only 2 unique digits "2" and "9" int this number.
If the given number is 1015, the function should return 3 because there are only 3 unique digits "1", "0" and "5" in this number.

//Code :

import java.io.*;
import  java.util.*;

class UserMainCode{

public int uniqueDigitsCount(int input1){

String str = Integer.toString(input1);

int len=str.length();

int count=0;

for(int i=0;i<len-1;i++){

for(int j=i+1;j<len;j++){

if(str.charAt(i)==str.charAt(j)) {

count++;
break;
}}
}
return len-count;
}}

## Question 4:

Non-Repeated Digits Count

Write a function to find the count to non-reapeated digits in a given number N. The number will be passed to the function as an input parameter of type int.
Assumption: The input number will be a positive integer number>= 1 and <=25000.
Some examples are as below-
If the given number is 292, the function should return 1 because there is only 1 non-repeated digit '9' in this number
If the given number is 1015, the function should return 2 because there are 2 non-repeated digits in this number, '0' and '5'.
If the given number is 108, the function should return 3 because there are 3 non-repeated digits in this number, '1', '0', and '8'.
If the given number is 22, the function should return 0 because there are NO non-repeated digits in this number.

//Code :

import java.io.*;
import  java.util.*;
class UserMainCode
{
public int nonRepeatDigitsCount(int input1){
String str = Integer.toString(input1);
int len=str.length();
int count=0,pcount=0;
for(int i=0;i<len;i++)
{
count=0;
for(int j=0;j<len;j++)
{
if(i!=j)
if(str.charAt(i)==str.charAt(j))
{
count++;
break;
}
}
if(count==0)
pcount++;
}
return pcount;
}
}

### SQL Queries   Android Project Ideas

1. import java.io.*;
import java.util.*;
class UserMainCode{
public int countPrimesInRange(int input1, int input2){

int count=0;
int pcount=0;
for(int i=input1;i<=input2;i++){

count=0;
for(int j=2;j<=Math.sqrt(i);j++) {

if(i%j==0)
count++;
}
if(count==0)
pcount++;
}
return pcount;
}}