C :

#include<stdio.h>
void main() 
{
	int i,q,b,s,g;
	scanf("%d",&i);
	q=i/1000;
	b=i/100%10;
	s=i/10%10;
	g=i%10;
	printf("%d",q+b+s+g);
}

C++ :

#include <bits/stdc++.h>
using namespace std;

int main(){
	int n,g,s,b,q;
	cin>>n;
	q = n / 1000;
	b = n / 100 % 10;
	s = n / 10 % 10;
	g = n % 10;
	cout<<q+b+s+g<<endl;
    return 0;
}

Pascal :

var
	n,a,b,c,d,e:integer;
begin
	read(n);
	a:=n div 1000;
	b:=n mod 1000 div 100;
	c:=n mod 100 div 10;
	d:=n mod 10;
	e:=a+b+c+d;
	write(e);
end.

Java :

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s=sc.nextInt()+"";
		String[] s1=s.split("");
		int n=0;
		for(int i=1;i<s1.length;i++){
			n+=Integer.parseInt(s1[i]);
		}
		System.out.println(n);
	}
}

Python :

n = int(input())
q = n // 1000 % 10
b = n // 100 % 10
s = n // 10 % 10
g = n // 1 % 10
su = q + b + s + g
print(su)