import java.util.Scanner; public class app1 { public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("请输入一个正整数:"); int num = input.nextInt(); if(num <= 0) { System.out.println("请输入正整数!"); System.exit(0); }
long sum = 0; for(int i=1; i<=num; i++) { sum += i; } System.out.println("1到" + num + "之间的整数和为:" + sum); } } 献丑了!
public class app1 { public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("请输入一个正整数:"); long num = input.nextInt(); if(num <= 0) { System.out.println("请输入正整数!"); System.exit(0); }
long sum = 0; sum = num *(num +1)/2; System.out.println("1到" + num + "之间的整数和为:" + sum); } } 稍微改动一下!
BufferedReader br = null; System.out.println("==>请录入一个整数:"); br = new BufferedReader(new InputStreamReader(System.in)); long i = 0l; try { String line = br.readLine(); while(line == null){ if(line == null || "".equals(line.trim())){ br.close(); br = null; System.out.println("==>请录入一个整数:"); br = new BufferedReader(new InputStreamReader(System.in)); line = br.readLine(); } } try{ i = Long.parseLong(line); }catch(NumberFormatException nf){ System.out.println("==>请输入一个合法的整数:"); sum(); } } catch (IOException e) { e.printStackTrace(); }finally{ try { br.close(); } catch (IOException e) { e.printStackTrace(); } }
long sum = 0; for(long j = 0 ; j <= i ; j++){ sum += j; } System.out.println("sum="+sum); 你要的是这样的吗?
import java.util.*; public class app { public static void main(String[] args) { Scanner scan = new Scanner(System.in); System.out.println(请输入一个数); int num=scan.nextInt(); if(num<0) { System.exit(0); } int sum = 0; for(int i=0;i<num;i++){ sum++; } System.out.println(sum); } }
import java.util.Scanner;
public class app1 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("请输入一个正整数:");
int num = input.nextInt();
if(num <= 0) {
System.out.println("请输入正整数!");
System.exit(0);
}
long sum = 0;
for(int i=1; i<=num; i++) {
sum += i;
}
System.out.println("1到" + num + "之间的整数和为:" + sum);
}
}
献丑了!
public class app1 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("请输入一个正整数:");
long num = input.nextInt();
if(num <= 0) {
System.out.println("请输入正整数!");
System.exit(0);
}
long sum = 0;
sum = num *(num +1)/2;
System.out.println("1到" + num + "之间的整数和为:" + sum);
}
}
稍微改动一下!
System.out.println("==>请录入一个整数:");
br = new BufferedReader(new InputStreamReader(System.in));
long i = 0l;
try {
String line = br.readLine();
while(line == null){
if(line == null || "".equals(line.trim())){
br.close();
br = null;
System.out.println("==>请录入一个整数:");
br = new BufferedReader(new InputStreamReader(System.in));
line = br.readLine();
}
}
try{
i = Long.parseLong(line);
}catch(NumberFormatException nf){
System.out.println("==>请输入一个合法的整数:");
sum();
}
} catch (IOException e) {
e.printStackTrace();
}finally{
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
long sum = 0;
for(long j = 0 ; j <= i ; j++){
sum += j;
}
System.out.println("sum="+sum);
你要的是这样的吗?
public class app {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println(请输入一个数);
int num=scan.nextInt();
if(num<0) {
System.exit(0);
}
int sum = 0;
for(int i=0;i<num;i++){
sum++;
}
System.out.println(sum);
}
}