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JAVA_HOME????????JDK11???????E:\jdk11??%JAVA_HOME%\bin?Win + R???cmd????????java?javac?java -version??????????????????????Eclipse?IDEA????????????????????????????????
File > New > Project?Java Project?????Next?project01???????Finish?src????????New Package???????????New Class?public static void main(String[] args)????public class Demo { public static void main(String[] args) { System.out.println("Hello Java"); }} ???Java?????????????????????byte?short?int?long?float?double?char?boolean?????Class?Interface?Array?
Java?8????????3?????????????????????
byte?1???short?2???int?4???long?8???float?4???double?8???char?2???boolean?4???Java??????????????????????????????????????????????????????????
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// while??while(??) { // ??}// do-while??do { // ??} while(??);// for??for(???; ????; ????) { // ??} break????????continue????????return?????????????????????????????????????????????
// ??????int[] array = new int[10];// ????????int[] array = {1, 2, 3, 4};// ??????int[] array;// ??????int[] array = new int[]{1, 2, 3, 4}; a[0] = 0;System.out.println(a[0]);for???length???int[] a = new int[]{1, 2, 3, 4};for(int i = 0; i < a.length; i++) { System.out.println(a[i]);} // ????int[] a = {8, 5, 6, 12, 10};for(int i = 0; i < a.length - 1; i++) { for(int j = 0; j < a.length - i - 1; j++) { if(a[j] > a[j + 1]) { int temp = a[j + 1]; a[j + 1] = a[j]; a[j] = temp; } }} // ????int[] a = {8, 5, 6, 12, 10, 15, 3, 20};int minIndex = 0, maxIndex = a.length - 1;int centerIndex = (minIndex + maxIndex) / 2;boolean found = false;int target = 12;while(!found) { if(a[centerIndex] == target) { found = true; System.out.println("??12???????????" + centerIndex); } else if(a[centerIndex] < target) { minIndex = centerIndex + 1; } else { maxIndex = centerIndex - 1; } centerIndex = (minIndex + maxIndex) / 2;} 转载地址：http://olsm.baihongyu.com/