Finding min and max between several integers

Question

Seeing the solution to this online on Stackoverflow https://stackoverflow.com/a/19200031/3185410 I tried to come up with another solution by setting max to -infinity and min to +infinity. The code here by @haccks works pretty fine.

#include <stdio.h>

int main()
{
int num, max, min;

printf ("Enter four numbers: ");
scanf ("%d", &num);
max = min = num;

for (int i = 0; i < 3; i++)
{ 
    scanf ("%d", &num);
    if (max < num)
        max = num;
    else if (min > num)
        min = num;
}

printf ("\n%d %d", max, min);
return 0;
}

Here's the one I came up with:

#include <stdio.h>
#include <limits.h>
void main()
{
int max,min,num,i;
min=INT_MAX;
max=INT_MIN;
for (i=0;i<=3;)
{
    i++;
    printf("Enter number %d : ",i);
    scanf("%d",&num);
    if (num>max) max=num;
    else if (num<min) min=num;
}
printf("max is %d and min is %d",max,min);
}

What am I doing wrong with that?

INT_MAX is the maximum value that you can store in an int so num cannot ever be more than INT_MAX and therefore if (num>max) is pointless. Ditto for min. — jarmod, Jan 11 '14 at 18:25
You don't understand. max=INT_MIN if num>max that means if num>INT_MIN. — OsomePersan, Jan 11 '14 at 18:28
the only problem I can see is that you have coupled your solution to int,if you like to change the numbers type to say long long you would have some more work to do — Ezra, Jan 11 '14 at 18:31
@Notlikethat Trying numbers 5, 6, 7, and 8 the max is 8 and the min is like 27474727273723... haha and it's NotLikeThat — OsomePersan, Jan 11 '14 at 18:40

score 2 · Accepted Answer · answered Jan 11 '14 at 18:29

2

If the users input 5 then 6 you have :

for 5 : 5>-inf => max = 5

for 6 : 6>5 => max = 6 but then min has become 5 and yet it is still INT_MAX.

If you put if instead of else if, you loose in performance but have the right output I think (I cannot test right now).

answered Jan 11 '14 at 18:29

Vulpo

873
1
9
25

Changed 'ELSE IF' with 'IF' it works! Pretty weird! Can anyone explain why? – OsomePersan Jan 11 '14 at 18:45
In the example I gave, instead of just setting the max at 5, it sets max at 5 and the min at five. – Vulpo Jan 11 '14 at 18:46
@user3185410 The `else` means that whenever you have a new `max`, you set that and skip checking `min`. If this always happens, `min` never gets set. – Notlikethat Jan 11 '14 at 18:49
@user3185410; *Can anyone explain why? *: To check the condition `num – haccks Jan 11 '14 at 19:04

score 0 · Answer 2 · answered Jan 11 '14 at 18:59

Set first input as min and max value. And then add logic you wrote. Here you had 2 lines of extra code but you don't have to sacrifice performance.

#include <stdio.h>
#include <limits.h>
void main()
{
int max,min,num,i=0;
min=INT_MAX;
max=INT_MIN;
printf("Enter number %d : ",i+1);
scanf("%d",&num);
min=num;
max=num;
for (i=1;i<=3;)
{
    i++;
    printf("Enter number %d : ",i);
    scanf("%d",&num);
    if (num>max) max=num;
    else if (num<min) min=num;
}
printf("max is %d and min is %d",max,min);
}

Finding min and max between several integers

2 Answers2