public?class?HelloWorld?{
????public?static?void?main(String[]?args)?{
????????
int?sum?=?0;?//?保存?1-50?之間偶數(shù)的和
????????
int?num?=?2;?//?代表?1-50?之間的偶數(shù)
????????
do?{
????????????
????????????
num?=?num?+?2;?
????????????sum+=num;
}?while?(num<=50);?//?滿足數(shù)值在?1-50?之間時(shí)重復(fù)執(zhí)行循環(huán)
????????
System.out.println("?50以?xún)?nèi)的偶數(shù)之和為："?+?sum?);
}
}

怎么結(jié)果是700呢？