编译器没有显示错误，但不知道为什么运行失败

Question

package practice;public class practice6{ private static int dayNumber; private int way; private static double sum; private static int[] number1={2,3,4,2,3,1}; private static int[] number2={2,5,4,1,0,1}; public void jisuan(int way){ switch(way){ case 1:new practice6().jisuan1();break; case 2:new practice6().jisuan2();break; } } public static void jisuan1(){ int dixin=dayNumber*40; int tichen=0; for(int a=0;a<=number1.length;a++){ tichen=5*number1[a]; } sum=dixin+tichen; } public static void jisuan2(){ int dixin=dayNumber*50; double tichen=0; for(int a=0;a<=number1.length;a++){ tichen=3*number1[a]; } sum=dixin+tichen; } public static void main(String[] args) { practice6 p6=new practice6(); p6.jisuan(2); }}

Answer 1

肯定是ArrayIndexOutOfBoundsException ,数组下标越界异常

Answer 2

for(int a=0;a<=number1.length;a++){
tichen=5*number1[a];
}

for(int a=0;a<=number1.length;a++){
tichen=3*number1[a];
}

数组下标越界

for(int a=0;a<number1.length;a++){
}

下标是从0--length-1的length个元素下标