What are reasons for infinite inputs?

Question

A lot of the times when I code lets say I have only one cin>> I run my code it compiles but I can do infinite inputs even though in my code I have one input. What is the reason for this?

I checked for infinity loops found none for the specific test case I was working with.

Here's the code if you want to see.

#include <iostream>

using namespace std;

int main()
{
    long long a,b,c;
    cin >> a >> b >> c;
    long long mx,mn;
    if(b >= a)
    {
        b = mx;
        a = mn;
    }
    if(a > b)
    {
        a = mx;
        b = mn;
    }
    int x;
    int r = c; 
      
    for(int i = mn; i <= mx; i++)
    {
        x = i;
        if(x - mn == mx - x)
        {
            for(int j = 0; j < x; j++)
            {
               c += r * r;
            }
            cout << c + (mx - mn);
            return 0;
        }
       
    }
}

[Uninitialized variable behaviour in C++](https://stackoverflow.com/questions/30172416/uninitialized-variable-behaviour-in-c) and [What happens when I print an uninitialized variable in C++?](https://stackoverflow.com/questions/30180417/what-happens-when-i-print-an-uninitialized-variable-in-c). — Jason, Nov 13 '22 at 13:32

score 0 · Accepted Answer · edited Nov 12 '22 at 18:27

0

The problem lies down here, you are re-assigning values of a and b with some unassigned variables.

if(b >= a){
     b = mx;
     a = mn;
}

if(a > b){
     a = mx;
     b = mn;
}

Rather you may want to initialize max and mn with newly assigned values a, b

if(b >= a){
   mx = b;
   mn = a;
}

if(a > b){
   mx = a;
   mn = b;
}

edited Nov 12 '22 at 18:27

Usitha Indeewara

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answered Nov 12 '22 at 06:38

Papai from BEKOAIL

1,469
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score 0 · Answer 2 · edited Nov 13 '22 at 13:12

I am not sure what you mean but infinite input here, so I am guessing you have cin >> a >> b>> c and you passed 1 2 3 4 as input then your input actually stored in input file buffer stdin and cin take needed part from it one by one so cin end taking first three integers and leaving the rest making it look like infinite input.

adding mistake in your code as also mentioned by @Papai from BEKOAIL

if(b >= a){
   b = mx;
   a = mn;
}

if(a > b){
   a = mx;
   b = mn;
}

by doing this you are changing value of a and b with garbage value, where value of mx and mn remains uninitialized with garbage value.

correct way of doing it:

if(b >= a){
   mx = b;
   mn = a;
}

if(a > b){
   mx = a;
   mn = b;
}

What are reasons for infinite inputs?

2 Answers2