利用break跳出循环的特性
void dofunction()
{
Object* a = new Object();
do
{
if(mA==1)
{
break;//本来这里要写 delete a;return;如果多个if就要重复写多个delete a;
}
if(mB=2)
{
break;
}
}while(0)
delete a;
}