if语句的C++多个条件

Ed *_*saj -6 c++ conditional-statements

任何人都知道为什么这不起作用.我怎么能满足多种条件.

    else if (studentoverall < 90; studentoverall>=80)
    {
        lettergrade = "B";
    }
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Bar*_*rry 9

使用逻辑AND(&&):

else if (studentoverall < 90 && studentoverall >= 80)
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