Question

下面的代码哪有错误，为什么老提示不兼容的类型啊

import java.util.regex.*;
import java.util.*;
public class Dc{
public static void main(String[] args){
int a1,d,n,S;
System.out.println("请输入首项a1:");
Scanner p1=new Scanner(System.in);
a1=p1.nextLine();
System.out.println("请输入公差d:");
Scanner p2=new Scanner(System.in);
d=p2.nextLine();
System.out.println("请输入项数:");
Scanner p3=new Scanner(System.in);
n=p3.nextLine();
S=n*a1+n*(n-1)/2;
System.out.println("您所求的等差数列的前n项的和:");
System.out.println(S);
}
}

Answer 1

import java.util.regex.*;
import java.util.*;
public class Dc{
public static void main(String[] args){
int a1,d,n,S;
System.out.println("请输入首项a1:");
Scanner p1=new Scanner(System.in);
a1=Integer.valueOf(p1.nextLine());//修改处
System.out.println("请输入公差d:");
Scanner p2=new Scanner(System.in);
d=Integer.valueOf(p2.nextLine());// 修改处
System.out.println("请孙悔输入项数:");
Scanner p3=new Scanner(System.in);
n=Integer.valueOf(p3.nextLine());//陵凯脊 修改处
S=n*a1+n*(n-1)/2;
System.out.println("您所求的等差数列的前n项的和:");
System.out.println(S);
}
}
应该将读入的String转尺渗化成Integer

Answer 2

nextLine();获取的是字符串当然格式不兼容了。改成nextInt();就好