ex18

Write a program that calculates S = 1 + 2 + …. + N. where N is entered on the keyboard by the user. Using the For-loop.

******** In Algorithm ********

Algorithm Variables i,S,N: integers Begin S ← 0 write("Enter an integer:") read (N) for i from 1 to N S ← S + i next write("the sum 1+2+...+",N,"=" S) End Result : ==> Enter an integer : 17 the sum 1+2+...+17 =153

******** In C ********

#include <stdio.h> int main(){ int i, S=0,N; printf ("Enter an integer :"); scanf("%d",&N); for (i=1; i<=N ; i++){ S = S + i ; } printf ("the sum 1+2+...+%d = %d" ,N,S); return 0; }

******** In C++ ********

#include <iostream> using namespace std; int main(){ int i, S=0,N; cout<<"Enter an integer :"; cin>>N; for (i=1; i<=N ; i++){ S = S + i ; } cout<<"the sum 1+2+...+"<<N<<" = "<<S; return 0; }

******** in Python ********

S = 0 n=int(input("Entrer N:")) for i in range (1,n+1): S = S + i print("La somme est:",S)

******** in JAVA ********

import java.util.Scanner;
class Main {
public static void main(String[] args){
Scanner sc = new Scanner (System.in);
System.out.print("Enter N:");
int N = sc.nextInt();
int i,S=0; 
   for (i=1; i<=N;i++) {
        S = S+i;
   } 
System.out.print("1+2+...+ "+N+" = : "+S);
}
}

********* in C# *******

using System;
public class Ex18 {
public static void Main(string[] args)
{ int i, S=0,N;
 Console.Write("Enter N :");
  N= int.Parse(System.Console.ReadLine());
   for (i=1; i<=N ; i++){
      S = S  + i    ;
   }
Console.WriteLine(" 1+2+...+ "+N+" = "+S);
  }
}