Problem in Using atoi function

[tapobratabag]

I am trying to enter a 1000 digit number and then find the greatest multiple of consecutive 5 digits.I was having problem to convert the char to int.
Can anyone plz help me.

#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
using namespace std;
int main(void)
{
char *cp="7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
int a[1000],i=0,current,newvalue,max,p;
while(i>=999)
{
a[i]=atoi(const char *cp);
i++;
}
cout<<i<<endl;
cout<<a[0]<<endl;
cout<<a[999]<<endl;
cout<<a[0]*a[999]<<endl;
max=a[0]*a[1]*a[2]*a[3]*a[4];
for(i=0;i<=995;i++)
{
newvalue=a[i]+a[i+1]*a[i+2]*a[i+3]*a[i+4];
if(newvalue>max)
max=newvalue;
}
cout<<max;
system("pause");
}

[SirSmilesaLot]

modify this part:

while(i>=999)
{
a[i]=atoi(const char *cp);
i++;
}

to

char* temp=cp;
while(i>=999 && *temp!=NULL)
{
a[i]=atoi(*temp);
i++;
temp++;
}