i am getting errors when i compile this program

```
#include <iostream>
#include <cctype>
using namespace std;
const int MAX_DIGITS = 20;
int size; // number of digits in the integer
int digit[MAX_DIGITS]; // the digits stored in reverse order
void inputBigInt (int a[], int& sizeA);
/
void outputBigInt(int a[], int sizeA);
void add (int a[], int sizeA, int b[], int sizeB, int sum[], int& sizeSum);
int main()
{
int a[MAX_DIGITS];
int sizeA;
int b[MAX_DIGITS];
int sizeB;
int sum[MAX_DIGITS];
int sizeSum;
char ans;
do
{
void inputBigInt ( a[MAX_DIGITS], sizeA);
void add ( a[MAX_DIGITS], sizeA, b[MAX_DIGITS], sizeB, sum[MAX_DIGITS], sizeSum);
void outputBigInt(a[MAX_DIGITS], sizeA);
cout << "\n Do you want to run this program again? (y,n)";
cin >> ans;
} while (ans =='y' || ans == 'Y');
return 0;
}
void inputBigInt (int a[], int& sizeA)
{
cout<< "Enter up to 19 digits and than press enter.";
for(char x; x< MAX_DIGITS;x++)
cin>> a[x];
}
void add (int a[], int sizeA, int b[], int sizeB, int sum[], int& sizeSum)
{
int x, carry=0, stop, temp;
if (sizeA > sizeB)
stop=sizeA;
else
stop=sizeB;
for (x=0; x<= stop && x< size; x++)
{
temp = a[x] + b[x]+ carry;
if (temp< 10)
{
carry=0;
sum[x]=temp;
}
else
{
carry=1;
sum[x]=temp-10;
}
if (carry !=0)
{
//overflow
sizeSum=0;
}
}
}
void outputBigInt(int a[], int sizeA)
{
for(int x=size-1;x>=0;x--)
cout<< a[x];
}
```

at each of the parts in red my compiler is giving me the same two errors

1. illegal use of type 'void' 2. too many initializers