int num =9;
switch (num) {
case 1:
System.out.println("aaa");
break;
case 2:
System.out.println("bbb");
break;
default:
System.out.println("vvv");
break : 跳出循環
int c=9;
while (c<16) {
System.out.println("第"+c);
c++;
}
int dc=0;
do {
System.out.println("do,第"+dc);
dc++;
} while (dc<6);
循環三要素
1.變量賦初始值 即:int dc=0;
2.循環操作主體 即:System.out.println("do,第"+dc);
3.變量值改變 即:dc++;
數組:
int[] arr=new int[5];
int[] arr1= {1,3,5,7,9};
int[] arr2=new int[]{0,1,4,6,8};
int a =arr.length;
System.arraycopy(arr, 0, arr1, 1, 4);數組的複制 源數組,源數組開始複制下标,目标數組,目标數組下标,複制長度。
arr=Arrays.copyOf(arr, arr.length+1); //數組擴容 (建立一個新的數組并将源數組資料複制進去)
//冒泡排序
int[] arrlist= {1,333,9,88,33};
for (int i = 0; i < arrlist.length-1; i++) { //控制輪
for (int j = 0; j < arrlist.length-i-1; j++) { //控制次
if (arrlist[j]>arrlist[j+1])
{
int t=arrlist[j];
arrlist[j]=arrlist[j+1];
arrlist[j+1]=t;
}
}
}