1:遍历数组

public static void printArray(int[] arr) {

System.out.print("[");

for(int x=0; x<arr.length; x++) {

if(x == arr.length - 1) {

System.out.print(arr[x]);

}else {

System.out.print(arr[x]+", ");

}

}

System.out.println("]");

}

2:获取最值

public static int getMax(int[] arr) {

int max = arr[0];

for(int x=1; x<arr.length; x++) {

if(arr[x] > max) {

max = arr[x];

}

}

return max;

}

public static int getMax(int[] arr) {

int min = arr[0];

for(int x=1; x<arr.length; x++) {

if(arr[x] < min) {

min = arr[x];

}

}

return min;

}

3:数组反转

public static void reverse(int[] arr) {

for(int start=0,end=arr.length-1; start<=end; start++,end--) {

int temp = arr[start];

arr[start] = arr[end];

arr[end] = temp;

}

}

4:查表法

String[] strArray = {"","星期一","星期二","星期三","星期四","星期五","星期六","星期日"};

int index = ???;

System.out.println(strArray[index]);

5:查找元素在数组中第一次出现的索引

public static int getIndex(int[] arr,int key) {

int index = -1;

for(int x=0; x<arr.length; x++) {

if(arr[x] == key) {

index = x;

break;

}

}

return index;

}