我有一个，如果elseif的语句来根据病情查马克和品位的标志。

I have an if elseif statement to check marks and grade the marks according to the condition.

int marks;
string grade;

if (marks>=80 && marks!>100)
{
  grade = "A1";
}
else if (marks>=70 && marks!>79)
{
  grade = "A2";
}

等等.....

and so on.....

，当我编译它，我得到了

however, when i compile it i got

运营商'和;＆功放;不能应用于类型为布尔和INT

Operator '&&' cannot be applied to operand of type 'bool' and 'int'

帮我解决提前it.thanks。

help me fix it.thanks in advance.

推荐答案

其他答案使人们知道，主要的问题是，＆GT;！不是一个运营商

Other answers have made it known that the main problem is that !> isn't an operator.

我想建议，既然你要测试是否标记在于你采取额外的进一步的步骤特定范围内来格式化你的条件的前pressions使用以下方式：

I'd like to suggest that since you're testing whether marks lies within particular ranges that you take an additional further step to format your conditional expressions to use the following pattern:

if (80 <= marks && marks <= 100)
{
  grade = "A1";
}
else if (70 <= marks && marks <= 79)
{
  grade = "A2";
}

这是一个简单的，也许微妙的变化，但我认为它使范围检查的意图更加清晰。

It's a simple and maybe subtle change, but I think it makes the range check intent much more clear.