CODEWITHSUNDEEP
c++memory-managementstack
user4325846
user4325846

Reputation: 3

Stack Corruption error around the int array in c++

I am trying to write some c++ code that is a demo for a formula but using Recursion. Here is my program and the error it throws.

Environment - Visual Studio 2012
Compilation - Successful
Runtime Exception -
Run-Time Check Failure #2 - Stack around the variable 'inputNumbers' was corrupted.

Code -

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


int FindNumber(int Numbers[],int index,int sum, int count)
{       

    if(count == 0)
        return sum;
    else if (count == 1)
    {
        sum -= Numbers[index-1];
        index = index -1;
        count = count-1;
        return sum = FindNumber(Numbers,index,sum,count);
    }
    else
    {
        sum += Numbers[index-1];
        index = index -1;
        count = count-1;
        return sum = FindNumber(Numbers,index,sum,count);
    }
}

void main()
{   
    int inputNumbers[50]; //declare the series of numbers
    int cnt = 0; //define and initailize an index counter for inserting the values in number series.
    int position = 7; //defines the position of the number in the series whose value we want to find.

    // insert the number series values in the int array.
    for (int i = 1; i < 51; i++)
    {
        inputNumbers[cnt] = i;
        cnt++;
        inputNumbers[cnt] = i;
        cnt++;
    }

    cnt=0;
    for (int i = 1; i < 51; i++)
    {
        cout<<inputNumbers[cnt]<<endl;
        cnt++;
        cout<<inputNumbers[cnt]<<endl;
        cnt++;
    }

    // set another counter variable to 3 since formula suggests that we need to substrat 3 times from the nth position
    // Formula : nth  = (n-1)th + (n-2)th - (n-3)th
    cnt = 3;
    int FoundNumber = 0;

    //Check if position to be found is greater than 3.
    if(position>3)
    {
        FoundNumber = FindNumber(inputNumbers,position,FoundNumber,cnt);
        cout<< "The number found is : " << FoundNumber<< endl;
    }
    else
    {
        cout<<"This program is only applicable for finding numbers of a position value greater than 3..."<<endl;        
    }

}

The entire program is working perfect as per the logic I expect and gives proper output when i debug it but throw exception while exiting the main() after execution is complete.
I see i am doing a really silly but an intricate memory management mistake[and cannot find it].
Any help is appreciated.

Upvotes: 0

Views: 175

Answers (2)

Klamer Schutte
Klamer Schutte

Reputation: 1093

For an array of length 50 you cannot access beyond element 49; so code should be like:

int inputNumbers[50]; //declare the series of numbers
int cnt = 0; //define and initailize an index counter for inserting the values in number series.

// insert the number series values in the int array.
for (int i = 0; i < 50; i++)
{
    inputNumbers[cnt] = i;
    cnt++;
}

And indeed as in the previous answer you probably want to increment cnt only once.

Upvotes: 1

Severin Pappadeux
Severin Pappadeux

Reputation: 20130

Aren't you filling twice the size of the array here?

for (int i = 1; i < 51; i++)
{
    inputNumbers[cnt] = i;
    cnt++;
    inputNumbers[cnt] = i;
    cnt++;
}

Upvotes: 3

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