如何修复此预期表达式错误？

Question

我正在尝试为项目编写代码，并且在我的 if else 语句中我想将 SWI 大于或等于 305 且小于或等于 395。我将如何在代码中放置这些限制？我尝试使用 <= 和 >=，但我认为位置不正确，我对如何修复它感到困惑。

#include <iostream>
#include <cmath>
using namespace std;

int main()
{

    double T,SWI,W;

    cout << "HELLO USER, PLEASE ENTER THE TEMPERATURE AND WIND SPPED TO PREDICT WEATHER FORECAST";
    cin >> T, W;

    SWI = 150*log10(T-49)+0.41*W+125*W/T;

    if (SWI < 305);{

        cout << "There is a low risk of severe thunderstorms.\n";
        cout << "However, still remain indoors and keep dry until the storm passes\n";

    }else if (SWI >= 305,SWI <= 395); {

        cout<< "Severe thunderstorms possible.\n";
        cout << "Please remain indoors and expect turbulant winds.\n";

    }else if(SWI > 395);{

        cout << "Severe thunderstorms imminent.\n";
        cout << "Stay off the roads and avoid any tall trees, possibility of tornadoes suspected.\n";
    }


    return 0;
} // end program

Answer 1

您有一些语法错误。你应该有这样的东西：


if (SWI< 305){ //remove ; in every if and else

cout<< "There is a low risk of severe thunderstorms.\n"; 
cout << "However, still remain indoors and keep dry until the storm passes\n";

}else if (SWI<=395) { // if the execution falls in here is because SWI>=305

cout<< "Severe thunderstorms possible.\n";
cout << "Please remain indoors and expect turbulant winds.\n";

}else if(SWI > 395){

cout<< "Severe thunderstorms imminent.\n";
cout << "Stay off the roads and avoid any tall trees, possibility of tornadoes suspected.\n"; }

return 0; }

Answer 2

语法错误太多。更正后的版本。

您可能还需要考虑检查 T。它必须是 >49 否则日志函数得到一个 -ve 输入。

#include <iostream>
#include <cmath>


int main()
{
    using namespace std;

    double T,SWI,W;

    cout << "HELLO USER, PLEASE ENTER THE TEMPERATURE AND WIND SPEED TO PREDICT WEATHER FORECAST";
    cin >> T;
    cin >> W;

    SWI = (150*log10(T-49))+(0.41*W)+(125*W/T);

    if (SWI < 305){

        cout << "There is a low risk of severe thunderstorms.\n";
        cout << "However, still remain indoors and keep dry until the storm passes\n";

    }else if (SWI <= 395) {

        cout<< "Severe thunderstorms possible.\n";
        cout << "Please remain indoors and expect turbulent winds.\n";

    }else {

        cout << "Severe thunderstorms imminent.\n";
        cout << "Stay off the roads and avoid any tall trees, possibility of tornadoes suspected.\n";
    }


    return 0;
} // end program

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