实现1+2+3...+n，要求不能使用乘除法循环条件判断选择相关的关键字

Posted 2022-12-03 xy913741894

实现1+2+3…+n，要求不能使用乘除法、循环、条件判断、选择相关的关键字

用sizeof求二维数组也行

class Test

public:
    Test()
    
        x++;
        sum += x;
    
    static int GetSum()
    
        return sum;
    

private:
    static int x;
    static int sum;
;

int Test::sum = 0;
int Test::x = 0;



int main()

    Test* p = new Test[10];
    int sum = Test::GetSum();
    cout << sum << endl;
    delete[] p;
    return 0;

class A;

A* arr[2];

class A

public:
    virtual int getSum(int n)
    
        return 0;
    
;


class B : public A

public:
    virtual int getSum(int n)
    
        return arr[!!n]->getSum(n - 1) + n;
    
;

int main()

    A a;
    B b;
    arr[0] = &a;
    arr[1] = &b;

    cout << b.getSum(10) << endl;
    return 0;

typedef int(*fun)(int n);

fun pFun[2];

int get0(int n)

    return 0;


int getSum(int n)

    return pFun[!!n](n - 1) + n;


int main()

    pFun[0] = get0;
    pFun[1] = getSum;

    cout << getSum(10) << endl;
    return 0;

int getSum(int n)

    int sum = 0;
    n && (sum += getSum(n - 1) + n);
    return sum;


int main()

    cout << getSum(10) << endl;
    return 0;