C language do while loop classic Level 2 questions

A classic second level problem , The error rate is relatively high ：

ask ： At the end of the program b The value of is ：

int a = 1,b = 10;
do
{
    b -= a;
    a++;
}while(b-- <0)

​

A. 9

B. -2

C.-1

D. 8

First do while No matter the condition is 0 Still for 1 Will cycle at least once , And this question is b > 0, So the condition is zero （ The condition is false ）, So only cycle once , Go through the cycle b The value is 9,but, After the cycle, there is another b--,b Self reduction 1 No implementation ,9 Self subtraction 1 obtain 8.