Finding largest and min number in an array with functions

Question

I am trying to write a C program that calculates the min and max value from entered numbers. I managed find the min and max value, but for some reason i cannot print out the values outside the function. This is my code:

#include <stdio.h>
#include <stdlib.h>

void find_largest_smallest(int a[], int n, int *largest, int *smallest)
{
    largest=smallest=a[0];
    int i;
    for(i=0; i<n; i++)
    {
        if (largest<a[i])
            largest=a[i];
    }


    for(i=0; i<n; i++)
    {
        //printf("%d\n", a[i]);
        if (smallest>a[i])
            smallest=a[i];
    }
    printf("Largest is %d\n", largest);
    printf("smallest is %d\n", smallest);
}

int main()
{
    int elem;
    int i;
    int *x;
    int *y;

    printf("How many elements you want to store ?:");
    scanf("%d", &elem);
    int store[elem];
    for(i=0; i<elem; i++)
    {
        printf("Enter a value to be stored:");
        scanf("%d", &store[i]);
    }

    find_largest_smallest(store, elem, &x, &y);

    printf("Largest value stored is %d and the smallest is %d.", *x, y);

    return 0;
}

Enable compiler warnings. And resolve them all. largest=a[i]; - largest is a pointer to int, a[i] is an int. — KamilCuk
– KamilCuk, Commented Sep 30, 2019 at 10:53
largest -> *largest etc. And turn on those compiler warnings. — Bathsheba
– Bathsheba, Commented Sep 30, 2019 at 10:53
And you can set the largest and the smallest in the same loop (there is no need to iterate twice) — David Ranieri
– David Ranieri, Commented Sep 30, 2019 at 10:54

Marco Bonelli · Accepted Answer · 2019-09-30 10:55:06Z

2

This:

largest=smallest=a[0];

Is wrong. You are assigning an integer to a pointer. What you should do is instead:

*largest = a[0];
*smallest = a[0];

Same goes for other assignments and reads:

if (*largest < a[i])
    *largest = a[i];

/* ... */

if (*smallest > a[i])
    *smallest = a[i];

/* ... */

printf("Largest is %d\n", *largest);
printf("smallest is %d\n", *smallest);

The declaration of x and y in main should just be int (not int *):

int x, y;

The call to printf in main is also wrong:

printf("Largest value stored is %d and the smallest is %d.", x, y);
//                         no asterisk needed here ----------^

answered Sep 30, 2019 at 10:55

Marco Bonelli

71k21 gold badges129 silver badges153 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Vlad from Moscow · Accepted Answer · 2019-09-30 11:04:19Z

1

The parameters largest and smallest have pointer types

void find_largest_smallest(int a[], int n, int *largest, int *smallest)
                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^

So within the function you have to dereference the pointers to access pointed objects.

For example

void find_largest_smallest(int a[], int n, int *largest, int *smallest)
{
    *largest = *smallest = a[0];
    int i;
    for ( i = 1; i<n; i++ )
    {
        if ( *largest<a[i] )
            *largest=a[i];
    }


    for ( i = 1; i<n; i++ )
    {
        //printf("%d\n", a[i]);
        if ( *smallest>a[i] )
            *smallest=a[i];
    }
    printf("Largest is %d\n", *largest);
    printf("smallest is %d\n", *smallest);
}

Pay attention to that you could find the largest and the smallest elements using only one loop. Apart this the function should calculates pointers to the largest and smallest elements instead of their values because in general the user can pass the size of the array equal to 0. In this case the function will have undefined behavior.

Also within main the variables x and y should have the type int. That is

int x;
int y;

//...

printf("Largest value stored is %d and the smallest is %d.", x, y );

edited Sep 30, 2019 at 11:04

answered Sep 30, 2019 at 10:58

Vlad from Moscow

313k27 gold badges204 silver badges358 bronze badges

3 Comments

Adrian Mole Over a year ago

Does your answer really add anything new to Marco's?

Vlad from Moscow Over a year ago

@Adrian It seems we were writing answers simultaneously.

Adrian Mole Over a year ago

Happens a lot, I know!

Collectives™ on Stack Overflow

Finding largest and min number in an array with functions

2 Answers 2

Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related