Programming Styles
- Imperative Style
– We tell the code
What to do and How to do it
import java.util.*;
import java.lang.*;
import java.io.*;
// The main method must be in a class named "Main".
class Main {
public static void main(String[] args) {
for(int i=1;i<8;i++){
System.out.printf("isPrime(%d)? %b\n",i,isPrime(i));
}
}
public static boolean isPrime(int number){
boolean divisible=false;
for(int i=2;i<number ;i++){
if(number%i ==0){
divisible=true;
break;
}
}
return number>1 && !divisible;
}
}
OUTPUT:
isPrime(1)? false
isPrime(2)? true
isPrime(3)? true
isPrime(4)? false
isPrime(5)? true
isPrime(6)? false
isPrime(7)? true
- Declarative Style
– We tell the code
What to do and NOT focus on how to do it . For example :using a library to tell what to do .
- Functional Style
– It is kind of declarative style of programming.
– All functional Style is declarative but not all declarative style is functional
class Main {
public static void main(String[] args) {
for(int i=1;i<8;i++){
System.out.printf("isPrime(%d)? %b\n",i,isPrime(i));
}
IntStream.range(1,8)
.forEach(i-> System.out.printf("isPrime(%d)? %b\n",i,isPrime(i)));
}
public static boolean isPrime(int number){
//think declaratviely and code functionally
//given a range 1-8 , then no number within that range divides the given number
//
return number>1 && IntStream.range(2,number)
.noneMatch(i-> number%i ==0);
}
}
