笨笨的程序求救....!!
import java.io.*;
import java.lang.Number;
import java.lang.Math;
public class guess
{
public static void main(String [] args)
{
try{
//boolean flag = false;
while(true)
{
System.out.println( "Please enter a number: ");
BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
String num = read.readLine();
String[] str = new String(); //这里报错
for( int i = 0; i <= num.length(); i++)
{
if ( str[i] > 'a ' && str[i] < 'z ' ) //这里报错
{
System.out.println( "Entered Wrongly ");
System.out.println( "Please enter again ");
continue;
}
}
int b = Integer.parseInt(num);
if ( b < 0 || b > 99 )
{
System.out.println( "Entered Wrongly! ");
System.out.println( "Please enter again ");
continue;
}
double s = Math.random() * 100;
if (b > s)
{
System.out.println( "large ");
}
else if ( b < s)
{
System.out.println( "Small ");
}
else
{
System.out.println( "equal ");
}
}
}
catch(IOException e){}
}
}
请高手帮我看看啊,我找了半天也没有找到原因
[解决办法]
你是不是想这样啊？
import java.io.*;
import java.lang.Number;
import java.lang.Math;
public class guess {
public static void main(String[] args) {
try {
//boolean flag = false;
outer: while (true) {
System.out.println( "Please enter a number: ");
BufferedReader read = new BufferedReader(new InputStreamReader(
System.in));
String num = read.readLine();
// String[] str = new String[num.length()]; //这里报错
for (int i = 0; i < num.length(); i++) {
if (Character.isDigit(num.charAt(i))==false) { //这里报错
System.out.println( "Entered Wrongly ");
System.out.println( "Please enter again ");
continue outer;
}
}
int b = Integer.parseInt(num);
if (b < 0 || b > 99) {
System.out.println( "Entered Wrongly! ");
System.out.println( "Please enter again ");
continue;
}
double s = Math.random() * 100;
if (b > s) {
System.out.println( "large ");
} else if (b < s) {
System.out.println( "Small ");
} else {
System.out.println( "equal ");
}
}
} catch (IOException e) {}
}
}
[解决办法]
把String[] str = new String();
改为
char[] str;
然后给 str 赋值，你的源程序里就没有给str赋值，
然后再把 str[i] > 'a ' && str[i] < 'z '
改为 character.isletter(str[i])
就可以了
