数组练习-1
class test { public static void main(String[] args) { char letter[] = {'a','l'}; int num[] = new int[26]; for(int i = 0;i < letter.length;i++){ num[letter[i] - 97]++; } for(int i = 0;i < num.length;i++){ if(num[i] != 0){ System.out.println((char)('a' + i) + "--" + num[i]); } } } }
import java.util.Scanner; class test { public static void main(String[] args) { int arr[] = new int[]{27,67,49,37,57,67,7,71,57,87}; int temp; for(int odd = 0,even = arr.length - 1;odd <= even;odd++,even--){ if(arr[odd] % 2 == 0 && arr[even] % 2 == 1){ temp = arr[odd]; arr[odd] = arr[even]; arr[even] = temp; }else if(arr[odd] % 2 == 1){ odd++; }else if(arr[even] % 2 == 0){ even--; } } for(int i = 0;i < arr.length;i++){ System.out.print(arr[i] + " "); } } }
class test { public static void main(String[] args) { int arr[] = new int[]{9,10,6,6,1,9,3,5,6,4}; int num = 0; for(int i = 0;i < arr.length - num;i++){ for(int j = i + 1;j < arr.length - num;j++){ if(arr[i] == arr[j]){ for(int k = j;k < arr.length - 1 - num;k++){ arr[k] = arr[k + 1]; } num++; } } } int arr_new[] = new int[arr.length - num]; for(int i = 0;i < arr_new.length;i++){ arr_new[i] = arr[i]; } for(int i = 0;i < arr_new.length;i++){ System.out.print(arr_new[i] + " "); } System.out.println(num); } }
import java.util.Scanner; class test { public static void main(String[] args) { Scanner scan = new Scanner(System.in); System.out.println("number"); int number = scan.nextInt(); int arr[][] = new int [number][]; for(int i = 0;i < arr.length;i++){ arr[i] = new int[i + 1]; } for(int i = 0;i < arr.length;i++){ arr[i][0] = 1;//放在外层循环中 arr[i][i] = 1; for(int j = 1;j < arr[i].length - 1;j++){//i=1,i=2时,循环没有运行 arr[i][j] = arr[i - 1][j - 1] + arr[i-1][j]; } } for(int i = 0;i < arr.length;i++){ for(int j = 0;j < arr[i].length;j++){ System.out.print(arr[i][j] + " "); } System.out.println(); } } }