Find Biggest num

[MrNoob]

I m trying to find the biggest number in the array but problem is that it keeps returning one

#include <stdio.h>
int FindBiggest(int *arr,int choice)
{
    int i;
	int num=0;
	for(i=0;arr[i]<=sizeof arr;i++) {
		    if(num<arr[i])
			    num=arr[i];
	}
	return num;
}    
int main(void)
{
    int arr[]={0,5,3};
    int result;
	result=FIND_NUM(arr,BIGGEST);
	printf("%d\n",result);
    getchar();
    return 0;
}

even though in my function i set the number to 0 first then after that we check with the if num<array whish ofcourse it is now it we set the num to array untill there no we found our biggest num i dunno its problem :s

[William Hemsworth]

Is there any code you aren't posting? what is FIND_NUM and BIGGEST? You can't use sizeof to work out the length of an array passed to a pointer, instead you have to allow the caller to pass the length of the array as a parameter.

[MrNoob]

yah i changed that i also changed in function the if better and still not working

#include <stdio.h>
int FindBiggest(int *arr)
{
    int i;
	int num=0;
	for(i=0;arr[i]<=3;i++) {
		    if(arr[i]>num)
			    num=arr[i];
	}
	return num;
}    
int main(void)
{
    int arr[]={0,5,3};
    int result;
	result=FindBiggest(arr);
	printf("%d\n",result);
    getchar();
    return 0;
}

now ofcourse 1st num is bigger than 0 whish should set num to 5 whats wrong now :S?

[jephthah]

your problem is here: for(i=0;arr[i]<=3;i++) your index is 'i' yet your conditional is based on the value of 'arr' at the index 'i'

fix that.

.

[William Hemsworth]

#include <stdio.h>

int FindBiggest(int *arr, [B]int length[/B])
{
  int i;
  int num = 0;

  for (i = 0; [B]i < length[/B]; i++) {
    if ( arr[i] > num )
      num = arr[i];
  }

  return num;
}    

int main(void)
{
  int arr[] = {0, 5, 3};
  [B]int length = sizeof(arr) / sizeof(arr[0]);[/B]
  int result;

  result = FindBiggest( arr, [B]length[/B] );
  printf( "%d\n", result );

  getchar();
  return 0;
}

I highlighted the changes, also you were looping through too many elements in the array by using <=.

[MrNoob]

i made it work now but what the diff between array and just normal i?

#include <stdio.h>
int FindBiggest(int *arr)
{
    int i;
	int num=0;
	for(i=0;i<3;i++) {//used to be for(i=0;array[i<3;i++)
		    if(arr[i]>num)
			    num=arr[i];
	}
	return num;
}    
int main(void)
{
    int arr[]={0,5,3};
    int result;
	result=FindBiggest(arr);
	printf("%d\n",result);
    getchar();
    return 0;
}

in first line in the for loop ?

[William Hemsworth]

>what the diff between array and just normal i?
It's two completely different things, i is just an integer, array is the element which is located at the index of i.

[MrNoob]

thnaks man but i got one more question i made also a find biggest and smallest but it alawys get last element

#include <stdio.h>
#define BIGGEST 1
#define Smallest 0
int FindBiggest(int *arr,int choice)
{
    int i;
	int num=0;
	for(i=0;i<3;i++) {
		if(choice){//find BIGGEST NUM
		    if(arr[i]>num)
			    num=arr[i];
		}
		else
		{
			num=1000;
			if(arr[i]<num)
				num=arr[i];
		}

	}
	return num;
}    
int main(void)
{
    int arr[]={0,5,3};
    int result;
	result=FindBiggest(arr,Smallest);
	printf("%d\n",result);
    getchar();
    return 0;
}

[William Hemsworth]

If you are working out the biggest number, you have to start off with the smallest possible value and keep looking for a bigger value.

To find the smallest, you have to do the opposite. Start off with the biggest possible value, and keep looking for a smaller one.

Also it is more efficient to put the for loop inside the if block instead of the other way round, here is the corrected code:

#include <stdio.h>
#include <limits.h>

#define Biggest   1
#define Smallest  0

int FindBiggest(int *arr, int length, int choice)
{
  int i;
  int num = 0;

  if ( choice == Biggest ) {
    for (i = 0; i < length; i++) {
      if ( arr[i] > num ) { // Look for a bigger value
        num = arr[i];
      }
    }
  }

  else if ( choice == Smallest ) {
    num = INT_MAX; // Make it start off with the biggest possible value
    for (i = 0; i < length; i++) {
      if ( arr[i] < num ) { // Look for a smaller value
        num = arr[i];
      }
    }
  }

  return num;
}

int main(void)
{
  int arr[] = {2, 1, 3};
  int length = sizeof(arr) / sizeof(arr[0]); // Works out the length of arr
  int result;

  result = FindBiggest(arr, length, Smallest);
  printf("%d\n", result);

  getchar();
  return 0;
}

[jephthah]

i made also a find biggest and smallest but it alawys get last element

because for the smallest, you set num=1000 every single time you go through the loop. arr will always be less than 1000 each time, so it stores it in num, each time.

EDIT: i see William already re-wrote your code for you. consider yourself (un)lucky, because i would have made you fix it yourself.

[MrNoob]

thanks alot guys for helping me out

[William Hemsworth]

>i see William already re-wrote your code for you. consider yourself (un)lucky, because i would have made you fix it yourself.
Perhaps I am too generous sometimes :P

[Ancient Dragon]

I would have done it slightly different what what William posted -- initialize the value of num with the first element of the array on line 10, then line 21 of his code could be deleted.

[jephthah]

i would have done it completely different than what william posted.

and it would be just as trivial.