如果聲明有問題？

我的程序已啓動並正在運行，但是我的if語句出現問題，導致「scalene」成爲除正確輸出之外的輸出（除非scalene是正確的輸出）。看看這個問題：如果聲明有問題？

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任何人都可以發現的bug？

triangleShape功能

# include "header.h" 

triangleType triangleShape(float sideLength1, float sideLength2, float sideLength3) 
{ 
    triangleType triangle; 

    if (sideLength1 + sideLength2 < sideLength3) 
     triangle = noTriangle; 
    else if (sideLength1 + sideLength3 < sideLength2) 
     triangle = noTriangle; 
    else if (sideLength3 + sideLength2 < sideLength1) 
     triangle = noTriangle; 
    else if (sideLength1 == sideLength2 == sideLength3) 
     triangle = equilateral; 
    else if (sideLength1 == sideLength2) 
     triangle = isoceles; 
    else if (sideLength1 == sideLength3) 
     triangle = isoceles; 
    else if (sideLength2 == sideLength3) 
     triangle = isoceles; 
    else 
     triangle = scalene; 

    return triangle; 
}

輸出功能

# include "header.h" 

void output (float sideLength1, float sideLength2, float sideLength3) 
{ 
    if (triangleShape (sideLength1, sideLength2, sideLength3) == noTriangle) 
     cout << "Side lenghts of " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << " would not form a triangle." << endl; 
    else if (triangleShape (sideLength1, sideLength2, sideLength3) == equilateral) 
     cout << "A triangle with sides of lengths " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << "would be " << 
     "an equilateral triangle."<< endl; 
    else if (triangleShape (sideLength1, sideLength2, sideLength3) == isoceles) 
     cout << "A triangle with sides of lengths " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << "would be " << 
     "an isoceles triangle."<< endl; 
    else (triangleShape (sideLength1, sideLength2, sideLength3) == scalene); 
     cout << "A triangle with sides of lengths " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << " would be " << 
     "a scalene triangle."<< endl; 
}

來源

2011-02-06 darko

在相關說明中，我建議您使用`switch` /`case`構造或查找表來避免所有這些`if'，這將使代碼更具可讀性並避免這種錯誤。 – 2011-02-06 01:09:42

除了任何其他問題，比較`if（sideLength1 == sideLength2 == sideLength3）`不會做你認爲的事情。 – Blastfurnace 2011-02-06 01:11:49

你必須在這條線一個額外的分號：

else (triangleShape (sideLength1, sideLength2, sideLength3) == scalene);

在刪除分號結束，和在行中添加if（或完全刪除檢查）。這導致在「else」之後的打印始終發生，因爲它成爲一個單獨的聲明。

，你可以做以下任一：

else if (triangleShape (sideLength1, sideLength2, sideLength3) == scalene) 
    cout << "A triangle with sides of lengths " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << " would be " << 
    "a scalene triangle."<< endl;

或者：

else // There are no other options here... 
    cout << "A triangle with sides of lengths " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << " would be " << 
    "a scalene triangle."<< endl;

話雖這麼說，你可能要考慮運行你的函數一次，並存儲結果，然後做你的支票反對那個結果（甚至使用switch statement）。

另外，正如Blastfurnace指出的那樣，您的比較不正確。您應該使用：

if ((sideLength1 == sideLength2) && (sideLength1 == sideLength3))

來源

2011-02-06 01:04:45

else (triangleShape (sideLength1, sideLength2, sideLength3) == scalene);

應該

else if (triangleShape (sideLength1, sideLength2, sideLength3) == scalene)

來源

2011-02-06 01:05:54 Charles

void output (float sideLength1, float sideLength2, float sideLength3) 
{ 
    if (triangleShape (sideLength1, sideLength2, sideLength3) == noTriangle) 
     cout << "Side lenghts of " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << " would not form a triangle." << endl; 
    else if (triangleShape (sideLength1, sideLength2, sideLength3) == equilateral) 
     cout << "A triangle with sides of lengths " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << "would be " << 
     "an equilateral triangle."<< endl; 
    else if (triangleShape (sideLength1, sideLength2, sideLength3) == isoceles) 
     cout << "A triangle with sides of lengths " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << "would be " << 
     "an isoceles triangle."<< endl; 
    else (triangleShape (sideLength1, sideLength2, sideLength3) == scalene); 
     cout << "A triangle with sides of lengths " << sideLength1 << " " << sideLength2 << " and " << sideLength3 << " would be " << 
     "a scalene triangle."<< endl; 
}

最後否則不應該在最後一個分號。

來源

2011-02-06 01:06:10

如果聲明有問題？

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