C++ 我的代码中有一个错误，可能是语法错误或if语句错误，我找不到。编程新手

这可能是我的第一个节目。它需要用户输入三角形，然后对它们进行分类，并输出数据所暗示的三角形。我在猜测，事情是如何工作的，只是为了玩C++，但是我遇到了一个问题。我没有从我的程序中得到预期的结果，虽然它们在以前并不完美，但我没有输入边长，而是输入第一个边长，它会自动跳过其他两个边长，并继续代码

#include <iostream>

using std::cout;
using std::cin;
int sideA, sideB, sideC, angleA, angleB, angleC, longest, middle, shortest, sumbc, sumac, sumab;
int main()
{
cout << "Enter an angle for angle A\n";
cin >> angleA;
cout << "Enter an angle for angle B\n";
cin >> angleB;
cout << "Enter an angle for angle C\n";
cin >> angleC;
sumbc = angleB+angleC;
sumac = angleA+angleC;
sumab = angleA+angleB;
if(angleA + angleB + angleC == 180){ // This confirms that the angles add to 180 to form a triangle
        cout << "This is a triangle!(Based on Angles)\n";

if(angleA == 90){ // These are for right angle triangles
        cout << "This is a real right triangle!(angleA is 90 degrees..)\n";
        cout << "Please enter the side lengths now\n";
        cout << "Side 1:\n";
        cin >> sideA;
        cout << "Side 2:\n";
        cin >> sideB;
        cout << "Side 3:\n";
        cin >> sideC;
        if(sideA > sideB && sideA > sideC){
            longest = sideA;
            cout << "Side 1 is the hypotenuse!\n";
        }
        else if(sideB > sideA && sideB > sideC) {
            cout << "Side 2 is the hypotenuse\n";
            longest = sideB;
        }
        else if(sideC > sideA && sideC > sideB){
            cout << "The hypotenuse is Side 3\n";
            longest = sideC;
        }
        if(longest == sideC && sideA == sideB) { //Determines what kind of triangle it is if the longest side is sideC
                cout << "This triangle is Right and Isosceles\n  ";

        }
        else if(longest == sideB && sideC == sideA){
                cout << "This triangle is Right and Isosceles\n  ";

        }
        else if(longest == sideA && sideB == sideC ){
            cout << "This triangle is Right and Isosceles\n  ";
        }
        else {
            cout << "This triangle is right and Scalene!\n";
        }


    }
if(angleB == 90){ // These are for right angle triangles

        cout << "This is a real right triangle!(angleB is 90 degrees..)\n";
        cout << "Please enter the side lengths now\n";
        cout << "Side 1:\n";
        cin >> sideA;
        cout << "Side 2:\n";
        cin >> sideB;
        cout << "Side 3:\n";
        cin >> sideC;
        if(sideA > sideB && sideA > sideC){ //Finds longest side
            longest = sideA;
            cout << "Side 1 is the hypotenuse!\n";
        }
        else if(sideB > sideA && sideB > sideC) {
            cout << "Side 2 is the hypotenuse\n";
            longest = sideB;
        }
        else if(sideC > sideA && sideC > sideB){
            cout << "The hypotenuse side is Side 3";
            longest = sideC;
        }
        if(longest == sideC && sideA == sideB) { //Determines what kind of triangle it is if the longest side is sideC
                cout << "This triangle is Right and Isosceles\n  ";

        }
        else if(longest == sideB && sideC == sideA){
                cout << "This triangle is Right and Isosceles\n  ";

        }
        else if(longest == sideA && sideB == sideC ){
            cout << "This triangle is Right and Isosceles\n  ";
        }
        else {
            cout << "This triangle is right and scalene!\n";
        }


    }
if(angleC == 90){ // These are for right angle triangles


        cout << "This is a real right triangle!(angleC is 90 degrees..)\n";
        cout << "Please enter the side lengths now\n";
        cout << "Side 1:\n";
        cin >> sideA;
        cout << "Side 2:\n";
        cin >> sideB;
        cout << "Side 3:\n";
        cin >> sideC;
        if(sideA > sideB && sideA > sideC){
            longest = sideA;
            cout << "Side 1 is the hypotenuse!\n";
        }
        else if(sideB > sideA && sideB > sideC) {
            cout << "Side 2 is the hypotenuse\n";
            longest = sideB;
        }
        else if(sideC > sideA && sideC > sideB){
            cout << "The hypotenuse is Side 3";
            longest = sideC;
        }
        if(longest == sideC && sideA == sideB) { //Determines what kind of triangle it is if the longest side is sideC
                cout << "This triangle is Right and Isosceles\n  ";

        }
        else if(longest == sideB && sideC == sideA){
                cout << "This triangle is Right and Isosceles\n  ";

        }
        else if(longest == sideA && sideB == sideC ){
            cout << "This triangle is Right and Isosceles\n  ";
        }
        else {
            cout << "This triangle is right and scalene!\n";
        }


    }
if(angleA == angleB && angleB == angleC){ // This is for equiangular/equilateral triangles

            cout << "This is an equiangular/equilateral triangle.\n ";
            cout << "Please enter the side lengths now\n";
            cout << "Side 1:\n";
            cin >> sideA;
            int periequal = sideA*3;
            int areaequal = sideA*sideA*.5;
            cout << "The area is : " << areaequal << std::endl << "The perimeter is: " << periequal << std::endl;
            cout << "This triangle is Isosceles, Equiangular, Equilateral, and Acute ";


            }

    if(angleA < 90 && sumbc != 120 && angleB < 90 && angleC < 90){ //deals with acute triangles
        cout << "This is an acute triangle!\n";
        cout << "Please enter the side lengths now\n";
        cout << "Side 1:\n";
        cin >> sideA;
        cout << "Side 2:\n";
        cin >> sideB;
        cout << "Side 3:\n";
        cin >> sideC;
        int AcuteIsoPeri = sideA + sideB + sideC;
            if (sideA == sideB){
                    cout << "This is an Acute, Isosceles Triangle. \n" << "With a perimeter of: " << AcuteIsoPeri;

            }
             else if(sideA == sideC){
                 cout << "This is an Acute, Isosceles Triangle. \n" << "With a perimeter of: " << AcuteIsoPeri;
            }
            else if(sideB == sideC){
                 cout << "This is an Acute, Isosceles Triangle. \n" << "With a perimeter of: " << AcuteIsoPeri;
            }
            else{
                cout << "This is an Acute, Scalene Triangle. \n" << "With a perimeter of " << AcuteIsoPeri;
            }

    } //end of angleA if statement
    if(angleA > 90){  //Deals with obtuse
    cout << "This angle is Obtuse, angle A is greater than 90..";
    cout << "Please enter the side lengths now\n";
        cout << "Side 1:\n";
        cin >> sideA;
        cout << "Side 2:\n";
        cin >> sideB;
        cout << "Side 3:\n";
        cin >> sideC;
            if (sideA == sideB){
                    cout << "This is an Obtuse, Isosceles Triangle. \n";

            }
            else if(sideA == sideC){
                 cout << "This is an Obtuse, Isosceles Triangle. \n";
            }
            else if(sideB == sideC){
                 cout << "This is an Obtuse, Isosceles Triangle. \n";
            }
            else{
                cout << "This is an Obtuse, Scalene Triangle. \n";
            }
}
        else if(angleB > 90){
    cout << "This angle is Obtuse, angle B is greater than 90..";
    cout << "Please enter the side lengths now\n";
        cout << "Side 1:\n";
        cin >> sideA;
        cout << "Side 2:\n";
        cin >> sideB;
        cout << "Side 3:\n";
        cin >> sideC;
                       if (sideA == sideB){
                    cout << "This is an Obtuse, Isosceles Triangle. \n";

            }
            else if(sideA == sideC){
                 cout << "This is an Obtuse, Isosceles Triangle. \n";
            }
            else if(sideB == sideC){
                 cout << "This is an Obtuse, Isosceles Triangle. \n";
            }
            else{
                cout << "This is an Obtuse, Scalene Triangle. \n";
            }
}
        else if(angleC > 90){
        cout << "This angle is Obtuse, angle C is greater than 90..";
        cout << "Please enter the side lengths now\n";
        cout << "Side 1:\n";
        cin >> sideA;
        cout << "Side 2:\n";
        cin >> sideB;
        cout << "Side 3:\n";
        cin >> sideC;
                    if (sideA == sideB){
                    cout << "This is an Obtuse, Isosceles Triangle. \n";

            }
        else if(sideA == sideC){
                 cout << "This is an Obtuse, Isosceles Triangle. \n";
            }
        else if(sideB == sideC){
                 cout << "This is an Obtuse, Isosceles Triangle. \n";
            }
        else{
                cout << "This is an Obtuse, Scalene Triangle. \n";
            }
}
        }




//scalene, obtuse, acute
return 0;
}

所以我可能不知道我在做什么，我是一个糟糕的程序员或者什么的，哈哈，但是当我输入这些信息时，我得到的是： 信息：角度是40114,26..它确定它是钝角，这是正确的，然后它要求边长，这也是我打算让它做的。。然后我输入第一个边长6.4，一旦我按下回车键，程序就会跳到末尾。我可能犯了一个找不到的语法错误，或者我使用if语句的方式完全错误。如果你能帮我解决这个问题，我将不胜感激！前几天开始研究C++，想把它应用到真实的东西上，这就是这个怪物是如何被创造出来的…

---

问题的症结在于，您试图将浮点/双精度转换为整数。cin不喜欢你这样混音。如果你把字母“a”放进去，同样的事情也会发生。尝试使用浮点而不是整数

编辑：澄清一下，我的意思是把你的边和角做成浮点数。只要我没有输入带小数点的数字，这个程序就对我有效

int sideA, sideB, sideC, angleA, angleB, angleC, longest, middle, shortest, sumbc, sumac, sumab;

所有变量都是int。这些变量只包含整数。您可能需要的类型是float或double，这是可以容纳实数的浮点类型：

double sideA, sideB, sideC, angleA, angleB, angleC, longest, middle, shortest, sumbc, sumac, sumab;

开始使用这些类型后，这些行将出现问题：

if(angleA + angleB + angleC == 180)
if(angleA == 90)

问题是，即使在纸上输入的值加起来可能是180，在计算机中，50.0+50.0+80.0可能等于179.9992或类似的值。看

您确定这三条if语句中的一条总是计算为true吗

如果没有，则不会为longest分配值，您将得到意外的结果

---

代码中还有其他问题，但我不再考虑这一点。祝你好运。

你有一个逻辑错误。程序编译和链接良好。如果出现语法错误，程序将无法运行compile@Nandu哦，好的，谢谢。我会更新问题。欢迎来到堆栈溢出。我不能重现你的错误。当您编写代码时，最好从一些小而简单、工作完美的东西开始，然后一次增加一点复杂性，在每一步进行测试。这样，您就不会在大型程序的任何地方寻找bug。如果你真的到了那里，试着把代码简化成一个简单的例子，这是产生错误的最简单的例子。对你和我们来说，这将使狩猎更加容易。@Beta好吧，一开始很简单。。当我在几个小时前开始使用它时，它只识别等角三角形，但我试图使它能够通过角度和两边对每种类型的三角形进行分类。我想我会放弃这一点，明天再试一次，记住这个建议-最小编码，当我编码这一点时，我一次只做一点，但我可能没有像我应该做的那样测试每一点代码。@user3739597查看对我答案的编辑。最长只适用于直角三角形。如果它只适用于直角三角形，那么它是否需要一个值？由于我的工作速度很快，而且我的知识非常有限，我确信这个程序中很少有正确或有效的部分。我还没有学习浮点数据类型，这似乎解决了问题。浮点数是我应该一直用于低位数十进制数的吗？取决于你需要什么。浮点数和双精度数可以，但并不总是有小数位数。这取决于数字的大小。我强烈建议您现在就开始研究这个问题，因为浮点取整可能会导致错误，这会让您搜索数天。

    if(sideA > sideB && sideA > sideC){
        longest = sideA;
        cout << "Side 1 is the hypotenuse!\n";
    }
    else if(sideB > sideA && sideB > sideC) {
        cout << "Side 2 is the hypotenuse\n";
        longest = sideB;
    }
    else if(sideC > sideA && sideC > sideB){
        cout << "The hypotenuse is Side 3\n";
        longest = sideC;
    }