1 生成随机数
2 对随机数进行排序
3 对随机数进行统计，将出现最多次数的随机数显示出来，并计算该随机数显示的次数
要求：熟练使用方法
public class RandomTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
int [] a = getRandomNumber(1,100,100);
System.out.println("max:"+max(a));
System.out.println("min:"+min(a));
getSameNumber(a);
}
public static int[] getRandomNumber(int min, int max ,int length) {
int[] a = new int[length];
int x = 0;
System.out.println("产生随机数");
for (int i = 0; i < length; i++) {
a[x] = (int) (Math.random() * (max - min ) + 1);
System.out.print(a[x]+ " \t");
if((i+1)%5==0) System.out.println();
x++;
}
return a;
}
public static int max(int[] a) {
int max = a[0];
for (int i : a) {
max = max > i ? max : i;
}
return max;
}
public static int min(int[] a) {
int min = a[0];
for (int i : a) {
min = min < i ? min : i;
}
return min;
}
public static void getSameNumber(int[] a) {
try {
int[][] b = new int[a.length][2];
for (int j = 0; j < a.length; j++) {
b[j][0] = a[j];
b[j][1] = 0;
}
for (int i : a) {
for (int j = 0; j < a.length; j++) {
if (i == b[j][0]) {
b[j][1]++;
}
}
}
int x1 = 0, x2 = 0;
for (int j = 0; j < a.length; j++) {
System.out.println(j + " " +b[j][0] + " : " + b[j][1]);
if(x2 {
x1=b[j][0];
x2=b[j][1];
}
}
System.out.println(x1 + " : " + x2);
} catch (Exception e) {
// TODO Auto-generated catch block
System.out.println(e.getMessage());
}
}
}
5.26
/**
* @param args
*/
public static void main(String[] args) {
try {
// TODO Auto-generated method stub
final int NUMBER_OF_PRIMES = 100;
final int NUMBER_OF_PER_PRIMES = 10;
int count = 0;
int number = 2;
while (count < number_of_primes) {
//System.out.println(number);
if (IfPrime(number) && IfPalindromic(number)) {
count++;
if (count % NUMBER_OF_PER_PRIMES == 0)
System.out.println(number);
else
System.out.print(String.valueOf(number) + "\t");
}
number++;
}
} catch (RuntimeException e) {
// TODO Auto-generated catch block
System.out.println(e.getMessage());
}
}
public static boolean IfPrime(int number) {
boolean isPrime = true;
for (int i = 2; i < number/2 + 1 ; i++) {
if (number % i == 0)
{
//isPrime = false;
return false;
}
}
return isPrime;
}
public static boolean IfPalindromic(int number) {
String numberStr=String.valueOf(number);
String t1 = numberStr.substring(0, 1);
String t2 = numberStr.substring(numberStr.length()-1,numberStr.length());
//System.out.println("t1:"+t1+" t2:"+t2);
if(t1.equals(t2))
{
return true;
}
else
{
return false;
}
/*
boolean isPalindromic = false;
int m = number;
int s = 0, x;
while (m != 0) {
x = m % 10;
m = m / 10;
s = s * 10 + x;
}
if (s == m)
isPalindromic = true;
return isPalindromic;
*/
}
5.27
public static void main(String[] args) {
final int NUMBER_OF_PRIMES = 100;
final int NUMBER_OF_PER_PRIMES = 10;
int count = 0;
int number = 2;
while (count < number_of_primes) {
if (IfPrime(number) && !IfPalindromic(number) && IfPrime(number)) {
count++;
if (count % NUMBER_OF_PER_PRIMES == 0)
System.out.println(number);
else
System.out.print(number + " ");
}
number++;
}
}
public static boolean IfPrime(int number) {
boolean isPrime = true;
for (int i = 2; i < number 2; i++) {
if (number % i == 0)
isPrime = false;
}
return isPrime;
}
public static boolean IfPalindromic(int number) {
boolean isPalindromic = false;
int m = number;
int s = 0, x;
while (m != 0) {
x = m % 10;
m = m / 10;
s = s * 10 + x;
}
if (s == m)
isPalindromic = true;
return isPalindromic;
}
public static int Palindromic(int number) {
int m = number;
int s = 0, x;
while (m != 0) {
x = m % 10;
m = m / 10;
s = s * 10 + x;
}
if (s == m)
return s;
else return 0;
}
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