# Java Exercises: Compute the sum of first n given prime numbers

## Java Basic: Exercise-232 with Solution

Write a Java program to compute the sum of first n given prime numbers.

Input:

n ( n ≤ 10000). Input 0 to exit the program.

Pictorial Presentation: Sample Solution:

Java Code:

``````import java.util.*;
public class Main {

public static void main(String[] args) throws java.io.IOException{
Scanner scan = new Scanner(System.in);
int count=0;
int sum=0;
System.out.println("Input a number (n<=10000) to compute the sum:");
int n=scan.nextInt();
for(int i=2;;i++){
if(prime(i)){
count++;
sum+=i;
if(count==n)break;
}
}
System.out.println("Sum of first "+n+" prime numbers:");
System.out.println(sum);
}
public static boolean prime (int n){
if(n==1)return false;
for(int i=2;i<=Math.sqrt(n);i++)
if(n%i==0)return false;
return true;
}
}
```
```

Sample Output:

```Input a number (n<=10000) to compute the sum:
100
Sum of first 100 prime numbers:
24133
```

Flowchart: Java Code Editor:

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## Java: Tips of the Day

Java: Anagrams

Generates all anagrams of a string.

```public static List<String> anagrams(String input) {
if (input.length() <= 2) {
return input.length() == 2
? Arrays.asList(input, input.substring(1) + input.substring(0, 1))
: Collections.singletonList(input);
}
return IntStream.range(0, input.length())
.mapToObj(i -> new SimpleEntry<>(i, input.substring(i, i + 1)))
.flatMap(entry ->
anagrams(input.substring(0, entry.getKey()) + input.substring(entry.getKey() + 1))
.stream()
.map(s -> entry.getValue() + s))
.collect(Collectors.toList());
}
```