BigInteger类实现重载运算符'+'(BigInteger Class Implementation Overload operator '+')

BigInteger类实现重载运算符'+'(BigInteger Class Implementation Overload operator '+')

我想创建一个在后端使用数组的bigInteger类。

BigInt a = 4321; // assume in BigInt class: array is {4,3,2,1} BigInt b = 2131; // assume in BignInt class: array is {2,1,3,1} BigInt sum = a + b; // array {6,4,5,1}

我写了这个函数来重载'+'运算符来添加这两个数字

int* operator+(const uint32& other) const{ uint32 sum[n]; for(int i=0; i<n; i++){ sum[i] = (*this[i]) + other[i]; } return sum; }

但它不起作用。

注意 ：假设要修复的数组大小。

我在Overload运算符'+'中没有回答我的问题， 在C ++中添加两个数组 ，我对这个问题做了更多澄清。

谢谢

I want to create a bigInteger class that uses arrays in backend.

BigInt a = 4321; // assume in BigInt class: array is {4,3,2,1} BigInt b = 2131; // assume in BignInt class: array is {2,1,3,1} BigInt sum = a + b; // array {6,4,5,1}

I wrote this function to overload '+' operator to add the two numbers

int* operator+(const uint32& other) const{ uint32 sum[n]; for(int i=0; i<n; i++){ sum[i] = (*this[i]) + other[i]; } return sum; }

but it doesn't work.

Note: assume the array size to be fixed.

My question was not answered in Overload operator '+' to add two arrays in C++ and I made more clarification on this question.

Thank you

最满意答案

当前的问题是你正在返回一个指向自动（即函数本地）变量的指针。 函数返回时，变量超出范围。 取消引用返回的指针会导致未定义的行为 。

我认为该方法的签名应如下所示：

class BigInt { BigInt operator+(const BigInt& other) const {...} ... }

换句话说，它应该引用BigInt一个实例，并且应该返回另一个BigInt实例（按值）。

The immediate problem is that you're returning a pointer to an automatic (i.e. function-local) variable. The variable goes out of scope the moment the function returns. Dereferencing the returned pointer would lead to undefined behaviour.

I would argue that the method's signature should look like this:

class BigInt { BigInt operator+(const BigInt& other) const {...} ... }

In other words, it should take a reference to an instance of BigInt and should return another instance of BigInt (by value).