JAVA實例：給一個不多於5位的正整數，要求：一、求它是幾位數，二、逆序打印出各位數字。
import java.util.Scanner;
publicclass Ex24 {
publicstaticvoid 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 + "是一位數");
System.
out.println("按逆序輸出是" + '\n' + a);
}
elseif(a >= 10 && a <= 99) {
System.
out.println(a + "是二位數");
System.
out.println("按逆序輸出是" );
tn.converse(a);
}
elseif(a >= 100 && a <= 999) {
System.
out.println(a + "是三位數");
System.
out.println("按逆序輸出是" );
tn.converse(a);
}
elseif(a >= 1000 && a <= 9999) {
System.
out.println(a + "是四位數");
System.
out.println("按逆序輸出是" );
tn.converse(a);
}
elseif(a >= 10000 && a <= 99999) {
System.
out.println(a + "是五位數");
System.
out.println("按逆序輸出是" );
tn.converse(a);
}
}
publicvoid 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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