题目:给一个不多于5位的正整数,要求:一、求它是几位数,二、逆序打印出各位数字。
程序设计:
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import java.util.Scanner;
public class Ex24 {
public static void main(String[] args) {
Ex24 tn = new Ex24();
Scanner s = new Scanner(System.in);
long a = s.nextLong();
if (a < 0 || a > 100000 ) {
System.out.println( "Error Input, please run this program Again" );
System.exit( 0 );
}
if (a >= 0 && a <= 9 ) {
System.out.println( a + "是一位数" );
System.out.println( "按逆序输出是" + '\n' + a);
} else if (a >= 10 && a <= 99 ) {
System.out.println(a + "是二位数" );
System.out.println( "按逆序输出是" );
tn.converse(a);
} else if (a >= 100 && a <= 999 ) {
System.out.println(a + "是三位数" );
System.out.println( "按逆序输出是" );
tn.converse(a);
} else if (a >= 1000 && a <= 9999 ) {
System.out.println(a + "是四位数" );
System.out.println( "按逆序输出是" );
tn.converse(a);
} else if (a >= 10000 && a <= 99999 ) {
System.out.println(a + "是五位数" );
System.out.println( "按逆序输出是" );
tn.converse(a);
}
}
public void converse( long l) {
String s = Long.toString(l);
char [] ch = s.toCharArray();
for ( int i=ch.length- 1 ; i>= 0 ; i--) {
System.out.print(ch[i]);
}
}
}
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