import java.util.ArrayList;
import java.util.List;
/**
* 新的for循环,格式为for(type x:type y)
* 表示遍历数组或集合y的元素,把元素值赋给x
*/
public class ForEach {
/**对整数数组求和*/
public static long getSum(int[] nums) throws Exception{
if(nums == null)
throw new Exception("错误的参数输入,不能为null!");
long sum = 0;
//依次取得nums元素的值并累加
for(int x : nums){
sum += x;
}
return sum;
}
/**对整数列表求和*/
public static long getSum(List<Integer> nums) throws Exception{
if(nums == null)
throw new Exception("错误的参数输入,不能为null!");
long sum = 0;
//可以与遍历数组一样的方式遍历列表
for(int x:nums){
sum += x;
}
return sum;
}
/**求多维数组的平均值*/
public static int getAvg(int[][] nums) throws Exception{
if(nums == null)
throw new Exception("错误的参数输入,不能为null!");
long sum = 0;
long size = 0;
//对于二维数组,每个数组元素都是一维数组
for(int[] x : nums){
//一维数组中的元素才是数字
for(int y : x){
sum += y;
size ++;
}
}
return (int)(sum/size);
}
public static void main(String[] args)throws Exception{
int[] nums = {456,23,-739,163,390};
List<Integer> list_I = new ArrayList<Integer>();
for(int i = 0; i < 5; i++){
list_I.add(nums[i]);
}
System.out.println(getSum(nums));
System.out.println(getSum(list_I));
int[][] numss = {{1,2,3},{4,5,6},{7,8,9,10}};
System.out.println(getAvg(numss));
}
}
