just a little help needed

Question

sahil_logic 0 Light Poster

20 Years Ago

#include<iostream.h>
#include<conio.h>
int main()
{
void sortarray(int array[15],int size);
void mergearray(int ar1[15], int ar2[15], int ar3[30],int m ,int n);
int m, n ,ar1[15],ar2[15],ar3[30],array[15],size;
cout<<" Enter the size of the arrays "<<endl;
cin>>m>>n;
cout<<" Enter the elements of first array "<<endl;
for(int i=0;i<m;i++)
cin>>ar1;


cout<<" Enter the elements of second array "<<endl;
for(int j=0;j<n;j++)
cin>>ar2[j];


sortarray(ar1,m);
sortarray(ar2,n);
mergearray(ar1,ar2,ar3,m,n);
getch();
}//****************End of main


void sortarray(int array[15],int size)
{
int temp=0;
for(int i=0;i<size;i++)
{
for(int j=i+1;j<size+1;j++)
{
if(array>array[j])
{temp=array;
array=array[j];
array[j]=temp;
}
}
}
}
void mergearray(int ar1[15],int ar2[15], int ar3[30] , int m ,int n)
{  if(m>n)
{
for(int i=0;i<n;i++)
{
if(ar1>ar2)
ar3=ar2;
else ar3=ar1;
}
for(int k=n;k<m;k++)
ar3[n]=ar1[n];
}
else
{
for(int i=0;i<m;i++)
{
if(ar1>ar2)
ar3=ar2;
else ar3=ar1;
}
for(int k=m;k<n;k++)
ar3[m]=ar1[m];
}


for(int k=0;k<m+n;k++)
cout<<ar3[k]<<"\t";
}

not getting the correct output .
i am basically trying to make a prog to accept the elements of two arrays then merging the two arrays and getting it sorted .
then printing it.there are no compile errors and the second array gets sorted while after that wat i get is a bunch of arbitrary values. plz indiate the faults.

c++

Edited 13 Years Ago by happygeek because: fixed formatting

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10 Replies
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Latest Post 20 Years Ago Latest Post by dwks

Dani AI

Generated 6 Months Ago

Several simple mistakes in the posted attempts explain the garbage output and make the program invoke undefined behavior.

The code often reads into or compares whole array names (for example cin >> ar1 or if (ar1 > ar2)), which uses the array pointer or address instead of an element.
Several loops use wrong bounds (size+1 or <=) or assign entire arrays (ar3 = ar2) instead of element slots; these lead to out‑of‑bounds writes and uninitialized reads (the source of the “big values”).
Nonstandard bits like conio.h/getch() and old headers were already noted by ; modern fixes avoid these and make debugging easier.

A compact, robust approach is to use standard containers and algorithms: read into vectors, sort each vector, then use std::merge (or a simple two‑pointer merge) to produce the final sorted result. That avoids manual index errors and capacity mistakes. Example (C++98/C++03 compatible):

#include <iostream>
#include <vector>
#include <algorithm>

int main() {
    int m, n;
    if (!(std::cin >> m >> n)) return 0;
    std::vector<int> a(m), b(n), c;
    for (int i = 0; i < m; ++i) std::cin >> a[i];
    for (int i = 0; i < n; ++i) std::cin >> b[i];
    std::sort(a.begin(), a.end());
    std::sort(b.begin(), b.end());
    c.reserve(m + n);
    std::merge(a.begin(), a.end(), b.begin(), b.end(), std::back_inserter(c));
    for (size_t i = 0; i < c.size(); ++i) std::cout << c[i] << (i+1==c.size()?'\n':' ');
    return 0;
}

Troubleshooting checklist inspired by the thread (, ): verify every cin uses an index, check inner loop bounds (j < size), never assign arrays as whole, and ensure the merge fills all m+n slots. Compile with warnings enabled (e.g. g++ -Wall -Wextra) and run with AddressSanitizer or Valgrind to catch out‑of‑bounds and uninitialized reads.

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SpS 34 Posting Pro

20 Years Ago

It is very difficult to read ur code...plz use code tags

dwks 149 Posting Whiz in Training

20 Years Ago

Don't use <iostream.h>. You should use this with the new standard:
```
#include <iostream>
using namespace std;
```
Ditto with getch(). It's non-standard.
main() returns int. And it should also return 0; while you're at it.
Don't rely on variables declared in for loops ( for(int x = 0; ... ) to be visible throughout the rest of the block. That is not part of the standard. Just re-declare the variable in all for loops, or at the top of the function or something.

And work on your indentation. :)

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sahil_logic 0 Light Poster · Answer 1 · 2005-11-22T18:46:22+00:00

sunnypalsingh - It is very difficult to read ur code...plz use code tags

#include<iostream.h>
#include<conio.h>
int main()
{
    void sortarray(int array[15],int size);
    void mergearray(int ar1[15], int ar2[15], int ar3[30],int m ,int n);
    int m, n ,ar1[15],ar2[15],ar3[30],array[15],size;
    cout<<" Enter the size of the arrays "<<endl;
    cin>>m>>n;
    cout<<" Enter the elements of first array "<<endl;
    for(int i=0;i<m;i++)
    cin>>ar1[i];

    cout<<" Enter the elements of second array "<<endl;
    for(int j=0;j<n;j++)
    cin>>ar2[j];

    sortarray(ar1,m);
    sortarray(ar2,n);
    mergearray(ar1,ar2,ar3,m,n);
    getch();
}//****************End of main

void sortarray(int array[15],int size)
{
     int temp=0;
     for(int i=0;i<size;i++)
     {
             for(int j=i+1[CODE];j<size+1;j++)
             {
                     if(array[i]>array[j])
                     {temp=array[i];
                      array[i]=array[j];
                      array[j]=temp;
                     }
             }
     }
}
void mergearray(int ar1[15],int ar2[15], int ar3[30] , int m ,int n)
{  if(m>n)
   {
     for(int i=0;i<n;i++)
     {
             if(ar1[i]>ar2[i])
             ar3[i]=ar2[i];
             else ar3[i]=ar1[i];
     }
     for(int k=n;k<m;k++)
     ar3[n]=ar1[n];
    }
    else
    {
      for(int i=0;i<m;i++)
      {
             if(ar1[i]>ar2[i])
             ar3[i]=ar2[i];
             else ar3[i]=ar1[i];
      }
      for(int k=m;k<n;k++)
      ar3[m]=ar1[m];
    }

     for(int k=0;k<m+n;k++)
     cout<<ar3[k]<<"\t";
}

sahil_logic 0 Light Poster · Answer 2 · 2005-11-22T18:50:25+00:00

how to make it more readable . if it is tags how to do it?? new to forums

mooni 0 Newbie Poster · Answer 3 · 2005-11-22T19:52:30+00:00

void mergearray(int ar1[15],int ar2[15], int ar3[30] , int m ,int n)
{  if(m>n)
{
for(int i=0;i<n;i++)
{
if(ar1>ar2)
ar3=ar2;
else ar3=ar1;
}
for(int k=n;k<m;k++)
ar3[k]=ar1[k];              // it must be k
}
else
{
for(int i=0;i<m;i++)
{
if(ar1>ar2)
ar3=ar2;
else ar3=ar1;
}
for(int k=m;k<n;k++)
ar3[k]=ar1[k];            // it must be k
}


for(int k=0;k<m+n;k++)
cout<<ar3[k]<<"\t";
}

sahil_logic 0 Light Poster · Answer 4 · 2005-11-22T20:11:52+00:00

void mergearray(int ar1[15],int ar2[15], int ar3[30] , int m ,int n)
{  if(m>n)
   {
     for(int i=0;i<=n;i++)
     {
             if(ar1[i]>ar2[i])
             ar3[i]=ar2[i];
             else ar3[i]=ar1[i];
     }
     for(int k=n;k<=m;k++)
     ar3[k]=ar1[k];
    }
    else if(n>m)
    {
      for(int i=0;i<=m;i++)
      {
             if(ar1[i]>ar2[i])
             ar3[i]=ar2[i];
             else ar3[i]=ar1[i];
      }
      for(int k=m;k<=n;k++)
      ar3[k]=ar1[k];
    }
    if(m==n)
    {for(int i=0;i<=n;i++)//made all the very strict conditions < or > to <= or >=
     {
             if(ar1[i]>=ar2[i])
             ar3[i]=ar2[i];
             else ar3[i]=ar1[i];
     }
     for(int k=n;k<=m;k++)
     ar3[k]=ar1[k];
    }
            
    
     for(int k=0;k<m+n;k++)
     cout<<ar3[k]<<"\t";
}

but still not getting the correct output. now first array gets sorted but again arbitrary values for second array

mooni 0 Newbie Poster · Answer 5 · 2005-11-22T21:14:19+00:00

My dear just tell me what u actually want to do.
what i've understood yet is that u want user to input two arrays then merge them and get the merged array sorted
like
a1 = {2,3,1,4}
a2 = {7,5,8,6}

what u want in output is
a3 = {1,2,3,4,5,6,7,8}
a1 = {2,3,1,4}
a2 = {7,5,8,6}

sahil_logic 0 Light Poster · Answer 6 · 2005-11-22T21:27:49+00:00

yes that is wat i want to do but i have realised that wat if in both the arrays (at the same location) same value is present . so i have included one extra check .m==n; .moreover the code is compiling without error but it is not giving the desired sorted array instead it sorts one of the array while i get some funny , big values or zeros for the second array.

mooni 0 Newbie Poster · Answer 7 · 2005-11-23T11:28:13+00:00

i believe u'll love it................
here is the correct code....... but u r requested to pray for me....
May Allah bless all of us

#include<iostream.h>
#include<conio.h>
void sortarray(int* array,int size);
void mergearray(int* ar1, int* ar2, int* ar3,int m ,int n);
void main()
{


int m, n ,ar1[15],ar2[15],ar3[30];
cout<<" Enter the size of the arrays "<<endl;
cin>>m>>n;
cout<<" Enter the elements of first array "<<endl;
for(int i=0;i<m;i++)
cin>>ar1;


cout<<" Enter the elements of second array "<<endl;
for(int j=0;j<n;j++)
cin>>ar2[j];


sortarray(ar1,m);
sortarray(ar2,n);


cout << "sorted ar1:  ";
for(i = 0;i<m;i++)
cout << ar1 << " ";
cout << "\nsorted Array2: ";
for (i = 0; i<n;i++)
cout << ar2 << " ";
cout << endl;
mergearray(ar1,ar2,ar3,m,n);
getch();
}//****************End of main


void sortarray(int* array,int size)
{
int temp=0;
for(int i=0;i<size;i++)
{
for(int j=i+1;j<size;j++)
{
if(array>array[j])
{temp=array;
array=array[j];
array[j]=temp;
}
}
}
}
void mergearray(int* ar1,int* ar2, int* ar3 , int m ,int n)
{
if(m>n)
{


for(int i=0;i<n;i++)
ar3=ar2;
for(int k=n;k<m+n;k++)
ar3[k]=ar1[k-n];
}
else if(n>m)
{
for(int i=0;i<m;i++)
ar3=ar2;
for(int k=m;k<n+m;k++)
ar3[k]=ar1[k-m];
}
if(m==n)
{
for(int i=0;i<n;i++)//made all the very strict conditions < or > to <= or >=
ar3=ar2;


for(int k=n;k<m+n;k++)
ar3[k]=ar1[k-n];
}
cout << "\nUnsorted Array3: ";
for(int i=0;i < m+n;i++)
cout << ar3 << " ";
sortarray(ar3,m+n);
cout << "\nsorted Array3: ";
for(int k=0;k<m+n;k++)
cout<<ar3[k]<<" ";
}

mooni 0 Newbie Poster · Answer 8 · 2005-11-23T11:30:57+00:00

if u need any further help do tell me.....always there

just a little help needed

Dani AI

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