falut error failure 的区别与理解

Fault的定义：可能导致系统或功能失效的异常条件（Abnormal condition that can cause an element or an item tofail.），可译为“故障”。

Error的定义：计算、观察或测量值或条件，与真实、规定或理论上正确的值或条件之间的差异（Discrepancy between a computed, observed or measured value or condition and the true, specified, or theoretically correct value or condition.），可译为“错误”。Error是能够导致系统出现Failure的系统内部状态。

Failure的定义：当一个系统不能执行所要求的功能时，即为Failure，可译为“失效”。（Termination of the ability of an element or an item to perform a function as required.）

1, findLast()

(1) 循环时缺少一个i=0的情况，应该为：

 

for(int i = x.length-1;i >= 0;i--)

(2) does not execute the fault

Test case: x=null y=2

Expected: NullPointerException

Actual: NullPointerException

 

(3) execute the fault but not cause error:

Test case: x = [1,2,5] y = 2

Expected: 1

     Actual: 1

(4) result error but not a failure:

Test case: x = [1,2,3] y = 5

Expected: -1

Actual: -1

 

2,lastZero()

 

(1) 要循环到最后一个，应该为

　　　　　　　　　　　　for(int i = x.length – 1;i>=0;i--)

(2) i=0应该被先执行

(3) Test case: x = [2,1,4]

Expected: i = -1

Actual: i = -1

(4)Test case: x = [0,1,2]

Expected: i = 0

Actual: I = 0

希望大家多多指教！