C :

#include <stdio.h>
int n, i, t;
int main(void) {
    scanf("%d", &n);
    for (i = 1; i <= n; i++) {
        if (i % 2) {
            t += i;
        }
    }
    printf("%d\n", t);
    return 0;
}

C++ :

#include<iostream>

using namespace std;

int main()
{
	int n,s;
	cin>>n;
	s=0;
	for (int i=1;i<=n;i++)
	{
		if (i%2==1)
		s=s+i;
	}
	cout<<s<<endl;
	return 0;
}

Pascal :

var a,b,c:longint;
begin
  readln(a);
  c:=0;
  for b:=1 to a do
      if b mod 2=1 then c:=c+b;
  writeln(c);
end.

Java :

import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner  cin = new Scanner (System.in );
    while (cin. hasNext ()){
    int a = 0;
    int  n =cin. nextInt ();
    for (int i = 1; i <= n ; i++) {
      if (i % 2 == 0) {
        continue;
      }
      a += i;
    }
    System.out.println(a);
  }
}
}

Python :

# coding=utf-8
n = int(input())
t = 0
for i in range(1, n + 1):
    if i % 2 :
        t = t + i
print(t)