function returning pointer: max value in c++

Question

enter image description here

I made that task but it turn to me a huge number not the maximum

my code is

    #include <iostream>
    using namespace std;
    int* max(int p[],int n);
   int main (){
     int n;
     int*A=new int;


int *p;

cout<<"enter the value of array";
cin>>n;
p=new int[n];
for(int i=0;i<n;i++){
cout<<"enter the element";
cin>>p[n];
}
A=(max(p,n));
cout<<"the maximum is"<<*A;
return 0;

}
int* max(int p[],int n)
{
   int maximum;
   maximum = p[0];
   for(int x=0;x<n;x++)
   {
       if(p[x]>maximum)
       {
           maximum=p[x];
           return &maximum;
       }
   }

   return  &maximum;
}

Is there a specific reason you have to use an image instead of pasting the text? Also, your indentation is shot... — Deduplicator, Nov 21 '14 at 11:57
Please format your code properly - currently it's pretty much unreadable. — Paul R, Nov 21 '14 at 11:59
If you really used C++, not those terrible raw arrays, you wouldn't have that problem. Also return `int`s by value — Bartek Banachewicz, Nov 21 '14 at 12:00
possible duplicate of [Can a local variable's memory be accessed outside its scope?](http://stackoverflow.com/questions/6441218/can-a-local-variables-memory-be-accessed-outside-its-scope) — The Forest And The Trees, Nov 21 '14 at 12:01
dont use pointer in function return it doesnt seem to be needed. — MSS, Nov 21 '14 at 12:03
You forget to delete your array. Use `vector` instead and it will delete itself for you. — Neil Kirk, Nov 21 '14 at 12:32

Vlad from Moscow · Answer 1 · 2014-11-21T12:18:48.120

0

The correct definition of the function can look the following way

int * max( int a[], size_t n )
{
    int *maximum = a;

    for ( size_t i = 1; i < n; i++ )
    {
        if ( *maximum < a[i] ) maximum = a + i;
    }

    return maximum;
}

Or

int * max( int a[], size_t n )
{
    int *maximum = a;

    if ( n != 0 )
    {
        for ( int *p = a + 1; p != a + n; ++p )
        {
            if ( *maximum < *p ) maximum = p;
        }
    }

    return maximum;
}

As for your function definition then you are returning pointer to a local variable that in general case will be destroyed after exiting the function. So the program has undefined behaviour.

Take into account that there is no any sense to allocate memory

int*A=new int;

You will get a memory leak.

Simply define

int *A;

Also you should know that there is standard algorithm std::max_element declared in header <algorithm> that performs the same task.

For example you could write

#include <algorithm>

//..

A = std::max_element( p, p + n );

edited Nov 21 '14 at 12:18

answered Nov 21 '14 at 12:13

Vlad from Moscow

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your function will return an address so how to appear the value that is at that address on the screen ? – Salma Nov 21 '14 at 12:26
@ Salma The same way as you do it yourself: cout<<"the maximum is"<<*A; – Vlad from Moscow Nov 21 '14 at 12:44
it returns to me a huge number i didn't how to solve this problem – Salma Nov 21 '14 at 12:48
@Salma It means you are doing something wrong compared with what I showed. – Vlad from Moscow Nov 21 '14 at 12:51
@ Salma Update statement cin>>p[i]; – Vlad from Moscow Nov 21 '14 at 13:11

function returning pointer: max value in c++

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