How to get the max and min from an array?

[queenie680]

Hi,

Does anyone know how to get the largest and smallest number from an array?

float salary[100];

then I have a for loop here that loads the array....now how do you get the largest and smallest number in the array? Thank you for your time =)

Serena

 

[Zyrenthian]

Loop through it with a variable max initialized to zero and if the current value > max, set min to the value.

Second, with an unsigned int set to negative 1 loop through and set it if it is greater then the current value.

negative 1 in and unsigned in is the max value of an int

Matt

 

[Leibnitz]

This looks a little bit complicated !
Here is some code that does the same thing.

#include <iostream.h>
#define _MAXSIZE_ 100
void main()
{
float max;
float min;
float array[_MAXSIZE_];
int size;
cout<<&quot;This program can determin the maximun and minimum &quot;<<endl;
cout<<&quot;of a sequence of 100 numbers or less.&quot;<<endl;
cout<<&quot;How long will be your sequence ?&quot;<<endl;
cin>>size;
if( size > _MAXSIZE_ )
cout<<&quot;This sequence is too big !&quot;<<endl;
else
{
for( int i = 0; i < size; i++ )
{
cout<<&quot;x&quot;<<i + 1<<&quot; = &quot;;
cin>>array;
}
}
min = array[0];
for( int j = 0; j < size; j++ )
{
if( array[j] < min )
min = array[j];
}
max = array[0];
for(j = 0; j < size; j++ )
{
if( array[j] > max )
max = array[j];
}
cout<<&quot;The maximum is: &quot;<<max<<endl;
cout<<&quot;The minimum is: &quot;<<min<<endl;
}

 

[queenie680]

Thank you so much for your help I really appreciate it!

 

[Leibnitz]

You are welcome !
Here is some little corrections to the original code.

#include <iostream.h>
#include <stdlib.h>
#define _MAXSIZE_ 100
void main()
{
float max;
float min;
float array[_MAXSIZE_];
int size;
cout<<&quot;This program can determin the maximun and minimum &quot;<<endl;
cout<<&quot;of a sequence of 100 numbers or less.&quot;<<endl;
cout<<&quot;How long will be your sequence ?&quot;<<endl;
cin>>size;
if( size > _MAXSIZE_ || size <= 0 )
{
if( size > _MAXSIZE_ )
cout<<&quot;This sequence is too big !&quot;<<endl;
else if( size <= 0 )
cout<<&quot;The size cant be a negative number.&quot;<<endl;
exit(0);
}
// gets the sequence elements for the user
for( int i = 0; i < size; i++ )
{
cout<<&quot;x&quot;<<i + 1<<&quot; = &quot;;
cin>>array;
}
//determin the minimum
min = array[0];
for( int j = 0; j < size; j++ )
{
if( array[j] < min )
min = array[j];
}
//determin the maximum
max = array[0];
for(j = 0; j < size; j++ )
{
if( array[j] > max )
max = array[j];
}
cout<<&quot;The maximum is: &quot;<<max<<endl;
cout<<&quot;The minimum is: &quot;<<min<<endl;
}

 

[Zyrenthian]

If you wanna get funky you can streamline the above with funcitons as follows

int max(int x, int y)
{
return (x>y ? x:y);
}

int min(int x, int y)
{
return (x<y ? x:y);
}

and in a for loop do

int minVal = array[0];
maxVal = array[0];
for(int i = 1;i<SIZE_OF_ARRAY;i++)
{
   maxVal = max(maxVal,array[i]);
   minVal = min(minVal,array[i]);
}

Or you could just put the one line of code in the functions into the for loop. When the loop is done, you have the max and min values

Matt

 

[benimm]

Hi,

I'm a new user to this forum, Would appreciate if anyone can help me in this:

I need to find the index of the minimum value in a float array: float vector[index]

Can anyone tell me how I can do that?

Thanks alot!!

 

[pankajkumar]

I think this is almost same as i told here yesterday..
Hope it helps..

#include &quot;stdafx.h&quot;
#include &quot;stdlib.h&quot;
#include &quot;conio.h&quot;
#include <stdio.h>

int main(int argc, char* argv[])
{
int i, j;
double a[4],ai;

a[0] = 9.3; /* a sentinel */
a[1] = 4.2; /* a sentinel */
a[2] = 7.6; /* a sentinel */
a[3] = 3.3; /* a sentinel */


for(i=0; i <4; i++)
{ /* invariant: a[1..i-1] sorted */
ai = a;
j = i-1;
while( a[j] > ai )
{ /* invariant: a[j+2..i] > ai */
a[j+1] = a[j];
j--;
}
/* a[1..j] <= ai < a[j+2..i] */

a[j+1] = ai;
/* a[1..i] is sorted */
}
for(int k=0;k<4;k++)
printf(&quot;\n%1.1f&quot;,a[k]);


printf(&quot;\nMin is=%1.1f&quot;,a[0]);
printf(&quot;\nMax is=%1.1f&quot;,a[3]);
return 0;
}

 

[chipperMDW]

While it's good for beginners to see how this code works, I feel compelled to point out that there's a much simpler and faster way to get the same result:

[tt]const int SIZE = 10;
int array[ SIZE ];

// fill array somehow...

cout << &quot;Minimum: &quot; << min_element( array, array + SIZE );
cout << &quot;Maximum: &quot; << max_element( array, array + SIZE );
[/tt]

min_element and max_element are in <algorithm>, in the std namespace.