C :

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

C++ :

#include<stdio.h>
#include<time.h>
#include<stdlib.h>
int main()
{
    //freopen("in","w",stdin);
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int n,ans=0;
        scanf("%d",&n);
        for(int i=1;i<=n;i++)ans+=i;
        printf("%d\n",ans);
    }

}

Java :

import java.util.Scanner;
class Main {
	public static void main(String[] args) {
		Scanner reader=new Scanner(System.in);
		ACMTest test=new ACMTest();
		int T=reader.nextInt();
		for(int i=0;i<T;i++){
			int first=reader.nextInt();
			System.out.println(test.add(first));
		}
	}
}
class ACMTest{
	int add(int a){
		int sum=0;
		for(int i=0;i<=a;i++){
			sum=sum+i;
		}
		return sum;
	}
}