int carry=0;

int prod,i,j,rem;
int base=10;

else if ( op == '*' ) //checks for operator, performs array multiplication
{
for(i=size-1; i>-1;i--)
{
for(int j=size-1; j>-1;j--)
{
prod =firNum[i]*secNum[j];
prod += carry;

if(prod>=base)
{
carry = (prod/base);
prod -= (carry*base);
}

else
{
carry = 0;
final[i+j] += prod;

if(final[i+j] >= base)
{
rem = (final[i+j]/base);
final[i+j] -= rem*base;
carry += rem;
}
if(final[i+j] >= base)
{
final[i+j-1] += (final[i+j]/base);
final[i+j] = final[i+j] % base;
}
}
}
}

If you really want an expert to help you, be sure to follow directions and type your subject in the School Subject box. Any other words, including obscure abbreviations, are likely to delay responses from a teacher who knows that subject well.

The program will not compile, because many variables are undefined (for C/C++/C# or Java).

You will need to define a variable before first use.

Also, an if statement cannot start with "else if".

Perhaps you have missed out a part of the code.

The given code snippet is performing an array multiplication operation for two numbers represented as arrays.

Here is a breakdown of the code:

1. Initialize variables:
- `carry` stores the carry value during multiplication.
- `prod` stores the product of two digits.
- `i` and `j` are loop variables.
- `rem` stores the remainder value.
- `base` represents the base of the number system being used (in this case, it is 10, decimal system).

2. Perform multiplication:
- The code checks if the operator (`op`) is '*'.
- If it is '*', the code enters a nested loop to iterate through each digit of both numbers.
- For each pair of digits, the product is computed by multiplying them (`firNum[i] * secNum[j]`).
- The carry value is then added to the product.
- If the product is greater than or equal to the base, the code calculates the carry and adjusts the product accordingly.
- Otherwise, the carry is set to 0.
- The resulting product is added to the corresponding position in the `final` array (`final[i+j]`).

3. Handle carry and overflow:
- If the sum in `final[i+j]` is greater than or equal to the base, the code calculates the remainder and adjusts the sum and carry.
- If the adjusted sum is still greater than or equal to the base, the code carries that value to the next position ( `final[i+j-1]`).
- The resulting sum is then stored in `final[i+j]`.

4. The code continues to iterate through each element of the arrays until all digits have been multiplied.

Overall, this code is performing array multiplication by iterating through the digits of both numbers and keeping track of carries and overflow in order to calculate the correct product.