Question

using namespace std;

//a class that will handle all the calculations requested by user

class MathOperations{
  public:
    void Message();
    int setSum(int,int);
    int setSuB(int,int);
    int setMul(int,int);
    float setDiv(float,float *);
    int setSqrt(int);
};

//Implementation:

void MathOperations:: Message(){
    cout<< " Welcome. This program simulates a calculator "<<endl;
}
// implementing the setters methods.
int MathOperations::setSum(int a, int b){

    int total;
    total = a + b;
    return total;
} 
int MathOperations:: setSuB(int a, int b){
    int total;
    total = a - b;
    return total;
}
int MathOperations:: setMul(int a, int b){
    int total;
    total = a * b;
    return total;
}

float MathOperations:: setDiv(float a, float *b){
    float result;
    if(b ==0){
        cout << "Using the Default Value of 1 because you can't devide by 0"<<endl;
    }
    else
        result = (a / *b);
    return result;
}

int MathOperations::setSqrt(int Square){
    int total;
    total = sqrt(Square);
    return total;
}

int main(int argc, const char * argv[])
{
    //creating instances of class MathOperations
    MathOperations add, sub, mul, div, sqrt;
    ///creating variable to hold user input

    int fnum;
    float snum;
    char opt= '0';

    //propt user for values
    cout << " Enter a Number"<<endl;
    cin >> fnum;

    cout << " Enter a second number " <<endl;
    cin >> snum;

    float total = div.setDiv(fnum, &snum);

    cout << total <<endl;


    cout << " What would you like to do '+','-','*','/' ?"<<endl;
    cin >> opt;

    switch (opt) {
      case '+' :
        {
            int total = add.setSum(fnum, snum);
            cout << " The Total Sum of both numbers is " << total <<endl;
        }
        break;
      case '-' :
        {
            int total = sub.setSuB(fnum, snum);
            cout << " The Subtraction of both Numbers is " << total << endl;
        }
        break;
      case '*' :
        {
            int total = mul.setMul(fnum, snum);
            cout << " The Multiplication of both Numbers is " << total << endl;
        }
        break;
      case '/' :
        {
            int total = div.setDiv(fnum, &snum);
            cout << " The Division of both Numbers is " << total <<endl;
        }
      default:
        cout << " Not a valid Option"<<endl;
    }

}

该部门工作不正常。我在这做错了什么？我正在尝试用它内部的数学运算创建一个类。我是初学者，想在这里做一些练习。你能告诉我具体做错的事吗？

Answer 1

函数div的第二个参数不应该是指针。至少我没有看到它成为指针的任何理由。

所以只需删除*和＆amp;来自变量snum。

Answer 2

你不是在setDiv函数中保护自己不被0除，因为你不是先将第二个浮点数比作0。您只是将其地址与NULL进行比较。

错误信息没有意义：程序没有以任何方式“使用1”。

如果指针恰好为NULL，则返回未初始化的值。

Answer 3

如果您说您使用的是1而不是0，则永远不会将b的值更改为1.

我怎样才能解决这个问题？

3 个答案: