一个看似简单的题 - 黑马程序员技术交流社区

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.regex.Pattern;
public class test11 {
/**
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); // BufferedReader继承自Readed类
System.out.print("please input:");
String str = br.readLine(); // 从文件中读一行读一行
//同正则判断str是否是数字
String regex = "\\d+";
boolean flag = Pattern.matches(regex, str);
int sum = 0;
if(flag) {
sum = count(str);
System.out.println(sum);
} else
System.out.println("你输入的不是正整数!");
}
public static int count(String str) {
int sum = 0;
int length = str.length();
int a[] = {0,1,10,100,1000,100000,100000};
int num = Integer.parseInt(str);
while(length != 0) {
sum += num / a[length];
num = num % a[length]; //n为余数
length--;
}
return sum;
}
}

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