Thread: debuging problem

Hi! I have written the following piece of code, it compiles and works fine, i can enter data in it, but the proble is: when i am tryng to dusplay entered data(numbers in my case) it crashes. I thnks that i am missng one small line of code, could anyone please tell me which line is it, and where am i suppose to put it? thanks.

Code:

 
#include <stdio.h>
#include <iostream>
#include <iomanip>

using namespace std;

void mergesort(int [], int [], int [], int, int);

int main()

{
    int A[50], B[50], C[100], m, n, i;
    
    cout << "*****************************************************************************" << endl;
    cout << setw(45) << " MERGE SORT PROGRAM " << endl;
    cout << "*****************************************************************************" << endl;

    cout << " How many elements would you like to have in your first array? (max 50): " << endl;
    cin >> m;

    cout << " Please enter the array of elements in ascending order: " << endl;
    for (i=0; i<m; i++)
         cin >> A[i];

    cout << " How many elements would you like to have in your second array? (max 50): " << endl;
         cin >> n;

    cout << " Please enter the array of elements in ascending order:" << endl;

    for (i=0; i<n; i++)
         cin >> B[i];
         
    mergesort(A, B, C, m, n);

    cout << "\n------The result of your sorted arrays is----" << endl;

    for (i=0; i<m+n; i++)

         cout << C[i];
             
    return 0;
}

void mergesort(int A[], int B[], int C[], int m, int n)
{
    int a=0, b=0, c=0;

    for (a=0, b=0, c=0; a<m && b<n;)
    {
        if (A[a]<B[b])

            C[c++] = A[a++];
        else

            C[c++] = B[b++];
    }
    if (a<m)
        while (a<m)

            C[c++] = A[a++];
    else
        while (b<n)

            C[c++] = B[b++];
}

the code itself is ok, it crashes on the following line:

Code:

mergesort(A, B, C, m, n);

    cout << "\n------The result of your sorted arrays is----" << endl;

    for (i=0; i<m+n; i++)

         cout << C[i];
             
    return 0;

before this line comes into action i can add numbers into the first array and second ,but for some reason it won't display the sorted array that uses entered numbers.

thats what it does, it just finishes execution and closes the window. But it supposed to show the results(output) for some reason it doesn't.If any one have some solution to it, please helppppp....

In Visual Studio, I usually just set a breakpoint at the tail of main, so it waits until I let the application return from main.

I don't know of a way to leave the console window in view.

im not sure how much this will help at all but...


do a cin.get(); after every cin << , this hasnt been much of an issue w/ me but i did notice a few times that the end of line or enter key left in the input gave me issues when compiling with visual c++.

the other thing is right before return 0; do another cin.get(); to keep the console up. if it still closes add another cin.get(); before return 0;

maybe thats the issue, i dunno tho.

yep, i was 100% correct, if you press enter or space or anything after each character it stays in the input buffer, and gets ignored by cin <<, anyway, try this, should work.

Code:

#include <stdio.h>
#include <iostream>
#include <iomanip>

using namespace std;

void mergesort(int [], int [], int [], int, int);

int main()

{
    int A[50], B[50], C[100], m, n, i;
    
    cout << "*****************************************************************************" << endl;
    cout << setw(45) << " MERGE SORT PROGRAM " << endl;
    cout << "*****************************************************************************" << endl;

    cout << " How many elements would you like to have in your first array? (max 50): " << endl;
    cin >> m;
	cin.get();

    cout << " Please enter the array of elements in ascending order: " << endl;
    for (i=0; i<m; i++)  
	{
		cin >> A[i];
		cin.get();
	}
    cout << " How many elements would you like to have in your second array? (max 50): " << endl;
         cin >> n;

    cout << " Please enter the array of elements in ascending order:" << endl;

    for (i=0; i<n; i++)
	{
         cin >> B[i];
		cin.get();
	}

    mergesort(A, B, C, m, n);

    cout << "\n------The result of your sorted arrays is----" << endl;

    for (i=0; i<m+n; i++)

         cout << C[i];
	cin.get();
    return 0;
}

void mergesort(int A[], int B[], int C[], int m, int n)
{
    int a=0, b=0, c=0;

    for (a=0, b=0, c=0; a<m && b<n;)
    {
        if (A[a]<B[b])

            C[c++] = A[a++];
        else

            C[c++] = B[b++];
    }
    if (a<m)
        while (a<m)

            C[c++] = A[a++];
    else
        while (b<n)

            C[c++] = B[b++];
}

you will notice i made your for loops that had a cin >> have a full code block and added cin.get() after each one, then i also added a cin.get(); right before the return 0;


that was the problem, the code wasn't crashing, there just was nothing left to execute and keep the console open. therefor terminating the process.

Originally Posted by anon

Before all these cin.get()s one should put a cin.ignore(), something like

Code:

cin.ignore(128, '\n');

Now cin.get() won't have anything to read immediately (left-over newlines, other unread input).

wait, tell me what that does.