CODEWITHSUNDEEP
c++
user11296360
user11296360

Reputation:

C++ program returns "abort() has been called" with no other errors?

I'm trying to make a program that will request a string from the user and transform it into a letter pyramid (example below).

Ex: If the user enters the string "12345" the program should display:

    1                                                                                                                  
   121                                                                                                                 
  12321                                                                                                                
 1234321                                                                                                               
123454321

My code is as follows: (I'm not done yet)

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    //gets input
    cout << "Enter the string you would like to be processed" << endl;
    string input;
    cin >> input;
    
    //bottom layer = bottommost layer on the pyramid | element amount = elements in any given layer. | layerNum is to determine which layer computer is on
    int bottomLayer = input.size();
    int elementAmount;
    int layerNum;
    //layerNum keeps track of the pyramid layer the loop is currently on. 1 is the top, bottom = the string's length
    for (layerNum = 1; layerNum <= bottomLayer; layerNum++)
    {
        //signifies the amount of elements in a given layer. eg: for layer 2, the amount of elements would be 2*2-1=3
        elementAmount = layerNum * 2 - 1;
        //this loop prints the numbers up to where the order reverses
        for (int strElement = 0; strElement < layerNum; strElement++)
        {
            cout << input.at(strElement);
        }
        //starts on the first reverse letter to be printed and prints the rest
        for (int strElement = layerNum - 2; strElement < elementAmount; strElement--)
        {
            cout << input.at(strElement);
        }

    }
}

The console window opens up as expected, and I can input my string. However, after I do so, it returns the first letter and an error pop-up appears:

Debug Error!
abort() has been called

Other than this, there are no error messages or even warnings. For one execution, there was a warning about comparing unsigned ints at line 28, which is this:

for (layerNum = 1; layerNum <= bottomLayer; layerNum++)

But it stopped appearing after I ran the program next. Any ideas on how I can get my program to run?

Upvotes: 1

Views: 325

Answers (2)

Louis Go
Louis Go

Reputation: 2588

There are some logical errors in second loop.

  1. strElement might be less than 0, because in int strElement = layerNum - 2, layerNum starts from 1.
  2. strElement Element decreases by 1 every loop, so it MUST be less than zero after several rounds.
  3. loop condition should be strElement> -1, so loop would be break once strElementis less than 0.

Note: > -1 might not be the correct logic. But strElement < elementAmount once passes, loop would let the strElement always less than 0 and run in infinite loop.

    //starts on the first reverse letter to be printed and prints the rest
    for( int strElement = layerNum - 2; ; strElement > -1; strElement--)
    {
        cout << input.at(strElement);
    }

Upvotes: 2

Christopher Miller
Christopher Miller

Reputation: 3461

This loop:

for (int strElement = layerNum - 2; strElement < elementAmount; strElement--)

sometimes passes to at the index -1 (occurs when layerNum = 1), which would cause an error.

Upvotes: 1

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