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I need to intake a number like: 200939915

After doing this, which I know how, I need to remove the first number so it becomes: 00939915

What is the best way to do this?

Mark Provan
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4 Answers4

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char *c = "200939915";
char *d = c + 1;
Matt K
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I will probably attract the downvoters but here is what I would do:

#include <iostream>
#include <math.h>

int main()
{
    int number;
    std::cin >> number;

    int temp = number;
    int digits = 0;
    int lastnumber = 0;
    while(temp!=0)
    {
        digits++;
        lastnumber = temp % 10;
        temp = temp/10;
    }

    number =  number % (lastnumber * (int)pow(10,digits-1));
    std::cout << number << std::endl;
    return 0;
}

obviously since you want it in c change std::cin to scanf (or whatever) and std::cout to printf (or whatever). Keep in mind though that if you want the two 00 to remain in the left side of the number, Kane's answer is what you should do. Cheers

0

To remove the first digit of a integer first reverse the number. now remove the last digit using %10. Now again reverse the number. Now we can see that the first digit of the number will be removed.

KIRAN
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    Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Nov 10 '21 at 06:02
  • Completely useless answer. If it's easy to remove the last digit, it's also easy to remove the first digit. But now we also have to reverse a number, which is another problem, so you just made two problems from one problem. And the answer would be much more useful if it contained the code demonstrating this solution (maybe you know a clever way of doing this that I'm not getting from your text). – wovano Nov 10 '21 at 07:01
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Here I used an alias (nCopy) for our original integer. Then counted the number of digits till ones place. Say n=1234, inside the while loop, it iterates for 3 times. So count=3.
The n now finally contains the ones place digit (/first digit, here 1) as looping condition is till n>10. Then we use pow function and calculate 103 = 1000. Then subtract it from the alias, 1234-1000 = 234. And finally copy the value to original integer.

#include <iostream>
#include <math.h>
using namespace std;

int main() 
{
    int n; cin >> n;
    int nCopy = n;
    int count = 0;
    while(n>10){
      n/=10; 
      count ++;
    }
    nCopy -= (n * pow(10, count));
    n = nCopy;
    cout << n;
    return 0;
}

Hope it helps :)

Kunal Dutta
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