how to know the last digit of a 1000 digit long number …

also can we also store such a large number in c++…

if yes, how…

# last digit

**callam2pm**#1

**sailesharya**#2

first calculate the length of the number, and den use the “percentile” method of calculating the last digit.

fo example:

no= 46484881454

here, no of digits= 11

so

lastdigit= no%pow(10,11)

where 10 is constant and 11 is the no of digits in the given number.

pow is the function in mths.h library file…

hope you lyk the answer.

thanks

**kuruma**#4

Hello,

It depends on how this 1000 digit number is given to you…

If it is given in input, you can read it as a string and you are done

If it is the result of a series of calculations that get more and more complex and possibly lead to overflow, then the best way is to use an array to hold the digits and perform grade-school arithmetics like you were taught when you were young

It will also obviously depend on the kind of operations being performed, but, for multiplications, you can read a post I made to solve the problem Small Factorials.

There, I briefly explain how to handle very large numbers using an array, you can find it here and I hope you find it helpful!

Best regards,

Bruno

**callam2pm**#5

u mean 2 say i shud store it in a string and then calculate its length … and then proceed.

**sunny_patel**#6

hi @callam2pm well i dont think you can store this big number as a “number” in c++.

The obvious solution is to use String. String is a sequence of characters. Unlike ints and longs which have a paticular predefined range, strings dont have any such restriction(Except for the memory limit itself!).

So, here is the c++ code you might be looking for.

```
#include<iostream>
#include<cstring>
using namespace std;
int main()
{
char num[1001];
cin>>num;
// if the number is exactly of 1000 digits always then to get the last digit simply:
// cout<<"the last digit is:"<<num[999];
// if the number isnt of 1000 digits exactly then u must find its length first:
int length = strlen(num); //this function returns the length of the string
cout<<"the last digit is: "<<num[length-1];
return 0;
}
```

Hope this helps

**sailesharya**#8

u can also store it in strng format. bt dere will be a prblm. u cant use mathematical operations on string format.

so its better to use long int , double… etc etc

**kuruma**#9

long int, double and etc etc as you say, can never, ever store a number which is 1000 digits long…So a string should be used… Plus, if only the last digit is needed, such operation can be done easily on a string.

**sunny_patel**#10

@sailesharya no you cannot use these inbuilt datatypes they can not store such a long number.

Go to this page and scroll down a bit you will see a table having range of various variables like char int, long etc. that will make thing clear for you