题目:统计任意一个数字的长度
方法一:先把数字转换为字符换,再直接用现成的函数统计长度即可
方法二:用API
- public class Test {
- final static int[] sizeTable = { 9, 99, 999, 9999, 99999, 999999, 9999999,
- 99999999, 999999999, Integer.MAX_VALUE };
- static int sizeOfInt(int x) {
- for (int i = 0;; i++)
- if (x <= sizeTable[i])
- return i + 1;
- }
- public static void main(String[] args) {
- System.out.println(sizeOfInt(1234));
- System.out.println(sizeOfInt(123));
- System.out.println(sizeOfInt(12345));
- System.out.println(sizeOfInt(12));
- }
- }
方法三:取模与累加
public class HelloWorld{ public static void main(String[] args){ int num = 999; int count = 0; /* String s = String.valueOf(num); count=s.length();*/ int a=0,b=1; while(b!=0) { count+=1; num=num/10; b=num%10; } System.out.println("它是个"+count+"位的数!"); } }