How can I multiply really big numbers c++

Question

I have the following code

      int i, a, z;
i = 2343243443;
a = 5464354324324324;
z = i * a;
cout << z << endl;

When these are

Answer 1

ints only hold 32 bits. When the result of a multiplication is larger than 2^31 - 1, the result rolls over to a large negative value. Instead of using the int data type, use long long int, which holds 64 bits.