CODEWITHSUNDEEP
c++
Mihaela Churenska
Mihaela Churenska

Reputation: 53

count the digits of a number with recursion

#include<iostream>
using namespace std;

bool recursion(int numb, int k, int br)
{
    if(br==1) return (numb==k);
    return k==(numb%10) || recursion(numb/10,k,br-1);

}

int main(){
    int num,n;
    cin>>num;
    n=num;
    int p;
    cin>>p;
    int br=1;
    while(n>10){
        n=n/10;
        br++;
    }
    cout<<br<<endl;
    cout<<recursion(num,p,br);
    return 0;
}

This is the whole program for counting the digits of a number , but it doesn't work for numbers with more than 10 digits. Does anybody know why?

Upvotes: 1

Views: 276

Answers (2)

mrk
mrk

Reputation: 3191

On a 32-bits machine, integers are 32 bits long. The largest signed integer you can get is 2^31 - 1 = 2147483647 which has 10 digits. You've got to use strings to allow for arbitrarily large numbers.

Upvotes: 0

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726599

First, your recursive program is not counting the digits in a number, it checks if a particular digit k is present within the last br digits of the number numb.

It does not work for numbers with more than ten digits because the largest number on your system that int can represent has ten digits. On 32-bit systems it is 2,147,483,647.

To make it work with more digits, use a larger data type - say, long long, or uint64_t.

Upvotes: 1

Related Questions