How to Create a Big Integer Class in C ?

How to Implement Big Int in C

Introduction

Working with numbers larger than the built-in data type long int requires a custom implementation called big int. Here's a general approach to designing a big int class in C .

Data Structure

Store the integer as a vector of smaller numbers, typically single digits or small base values. This allows for arbitrary length integers.

template<class basetype>
class BigInt {
    typedef typename BaseType BT;
protected:
    std::vector<basetype> value_;
};</basetype></class>

Arithmetic Operations

Addition:

Implement the = operator using binary addition principles. Loop through the elements, performing addition and handling carries as needed.

template<class basetype>
BigInt<basetype>& BigInt<basetype>::operator+=(BigInt<basetype> const& operand) {
    BT count, carry = 0;
    for (count = 0; count <p><strong>Other Operations (Multiplication, Division, etc.)</strong></p>
<p>Other arithmetic operations leverage the implemented  = and -  operators. Consider using existing algorithms for optimized implementations.</p>
<p><strong>Other Considerations</strong></p>
<ul>
<li>Implement comparison operators (, etc.) by comparing the individual elements.</li>
<li>Befriend the standard input and output operators for convenient input and output.</li>
<li>Ensure that the underlying BaseType is the second largest available (e.g., 32-bit int on a 64-bit system) to handle carries correctly.</li>
</ul></basetype></basetype></basetype></class>

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