Question

问一个java编程问题，求高手帮我找出错误，谢谢啦！

我贴出代码：

package test11111111;

import java.math.BigDecimal;

public class ha {

private static boolean isNum(char c) {
try {

new BigDecimal(c);
return true;
} catch (Exception e) {
return false;
}
}

public static void main (String args[]){

String LNUM="";
int flag=0;
String str="100h100";
if(flag<str.length()){
while(isNum(str.charAt(flag))){

String Lnum=String.valueOf(str.charAt(flag));

LNUM=LNUM+Lnum;

flag++;
}

}

System.out.println(LNUM);

}
}
我想让程序输出的结果是100,怎么改正，求大神指导，谢谢啦！

Answer 1

参考下：

package test11111111;

public class ha {

	public static void main(String args[]) {

		String LNUM = "";
		int flag = 0;
		String str = "100h100";

		while (flag < str.length()) {
			if (Character.isDigit(str.charAt(flag))) {
				String Lnum = String.valueOf(str.charAt(flag));

				LNUM = LNUM + Lnum;

				flag++;
			} else {
				break;
			}
		}

		System.out.println(LNUM);

	}
}

Answer 2

package test11111111;

public class Test {
    private static boolean isNum(char c) {
        //Remeber the ASCII value of "0" to "9" is 48 to 57
        int asciiValue = c-0;
        if(c<48 || c>57){
            return false;
        }else{
            return true;
        }
    }
    
    public static void main (String args[]){
        String LNUM="";
        int flag=0;
        String str="100h100";
        if(flag<str.length()){
            while(isNum(str.charAt(flag))){
                String Lnum=String.valueOf(str.charAt(flag));
                LNUM=LNUM+Lnum;
                flag++;
            }
        }
        System.out.println(LNUM);
    }
}

Answer 3

你说的这个我只是知道皮毛

Answer 4

package test11111111;
public class ha {
private static boolean isNum(char c) {
return Character.getType(c) == Character.DECIMAL_DIGIT_NUMBER;
}
public static void main(String args[]) {
String LNUM = "";
int flag = 0;
String str = "100h100";
while (flag < str.length()) {
if (isNum(str.charAt(flag))) {
String Lnum = String.valueOf(str.charAt(flag));
LNUM = LNUM + Lnum;
flag++;
} else {
break;
}
}
System.out.println(LNUM);
}
}

Answer 5

package com.skytech.xyj;

public class bigDemical {
private static boolean isNum(char c) {

if (Character.isDigit(c)) {
return true;
}
return false;

}

public static void main(String args[]) {
String LNUM = "";
int flag = 0;
String str = "100h100";
if (flag < str.length()) {

while (isNum(str.charAt(flag)) && flag < str.length() - 1) {
String Lnum = String.valueOf(str.charAt(flag));
LNUM = LNUM + Lnum;
flag++;
}
}

System.out.println(LNUM);
}
}