C# If…Else语句C中的表达式项无效#

当我试图在

VSL studio 2012

中创建一个

控制台

应用程序，根据用户输入的温度输出关于穿什么的建议时，我遇到了错误

“无效的表达式项”

在这段代码中的每一条if语句上。我不知道我在这里做错了什么

如果有人能为我指出解决这个问题的正确方向，那将是令人惊讶的！ 多谢各位

if (temp <= 40)
{
    Console.WriteLine(" It is very cold. Put on a heavy coat.");
}
else if (temp > 40 && <= 60)
{
    Console.WriteLine("It is cold. Put on a coat.");
}
else if (temp > 60 && <= 70)
{
    Console.WriteLine("The temperature is cool. Put on a light jacket.");
}
else if (temp > 70 && <= 80)
{
    Console.WriteLine("The temperature is pleasent. You can wear anything you like");
}
else if (temp > 80 && <= 90)
{
    Console.WriteLine(" The temperautre is warm, you can wear short sleeves.");
}
else (temp > 90)
{
    Console.WriteLine("It is hot. You can wear shorts today.");
}

if（温度40&&60&&70&&80&&90）
{
WriteLine（“天气很热，你今天可以穿短裤。”）；
}

这是无效的语法：

else if (temp > 40 && <= 60)

---

else如果（temp>40&&40&&temp您编写了无效表达式：

(temp > 40 && <= 60)

（temp>40&&40&&temp正如Erik所说，您必须“重复”变量以进行另一次比较。
不能将“else”放在布尔表达式后面（else应该只是“else{}”），应该将if放在else后面，如下所示：

反而

else (temp > 90)

使用

因此，您的整个代码应该是：

if (temp <= 40)
            {
                Console.WriteLine(" It is very cold. Put on a heavy coat.");
            }
            else if (temp > 40 && temp <= 60)
            {
                Console.WriteLine("It is cold. Put on a coat.");
            }
            else if (temp > 60 && temp <= 70)
            {
                Console.WriteLine("The temperature is cool. Put on a light jacket.");
            }
            else if (temp > 70 && temp <= 80)
            {
                Console.WriteLine("The temperature is pleasent. You can wear anything you like");
            }
            else if (temp > 80 && temp <= 90)
            {
                Console.WriteLine(" The temperautre is warm, you can wear short sleeves.");
            }
            else if (temp > 90)
            {
                Console.WriteLine("It is hot. You can wear shorts today.");
            }

if（温度40&&temp 60&&temp 70&&temp 80&&temp 90）
{
WriteLine（“天气很热，你今天可以穿短裤。”）；
}
If应该是，例如，
temp>40&&temp在else关键字之后允许有条件吗？我的疏忽太大了…谢谢你指出这一点。谢谢你指出我的疏忽。
else (temp > 90)

else if (temp > 90)

if (temp <= 40)
            {
                Console.WriteLine(" It is very cold. Put on a heavy coat.");
            }
            else if (temp > 40 && temp <= 60)
            {
                Console.WriteLine("It is cold. Put on a coat.");
            }
            else if (temp > 60 && temp <= 70)
            {
                Console.WriteLine("The temperature is cool. Put on a light jacket.");
            }
            else if (temp > 70 && temp <= 80)
            {
                Console.WriteLine("The temperature is pleasent. You can wear anything you like");
            }
            else if (temp > 80 && temp <= 90)
            {
                Console.WriteLine(" The temperautre is warm, you can wear short sleeves.");
            }
            else if (temp > 90)
            {
                Console.WriteLine("It is hot. You can wear shorts today.");
            }