java 从一加到任意值

java 从一加到任意值

import java.util.Scanner;

public class TestScan {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("请输入一个整数：");
int n=sc.nextInt();
int count=0;
for(int i=1;i<=n;i++){
count=count+i;
}
System.out.println("1—"+n+"的和是： "+count);
}
}

public static void main(String[] args) {
// TODO Auto-generated method stub
int n;
Scanner in = new Scanner(System.in);
n = in.nextInt();
System.out.println("从1加到"+n+"的结果是:"+((1+n)*n)/2);
}

int sum = 0;
sum = (1+n)*n/2;

public static void main(String[] args) {
// 输入 n 的值
int n = 500;
long total = 0;
for (int i = 1; i <= n; i++) {
total += i;
}
System.out.println("总计:=" + total);
}

import java.util.Scanner;
public class Test {
public static void main(String[] args) {
System.out.print("请输入一个整数:");
int n = new Scanner(System.in).nextInt();
int sum = 0;
for(int i = 1; i <= n; i++){
sum += i;
}
System.out.println("从1加到" + n + "和为" + sum );
}
}
-----------测试结果
请输入一个整数:8
从1加到8和为36

import java.util.Scanner;
public class TestIn {
public static void main(String[] args) {
Scanner scanner=new Scanner(System.in);
System.out.println("请输入一个整数：");
int n=scanner.nextInt();
int sum=0;
for (int i=1;i<=n;i++){
sum+=i;
}
System.out.println("从1到"+n+"的和为:"+sum);
}
}