Where are
MINandMAXdefined in C, if at all?
They aren't.
What is the best way to implement these, as generically and type safe as possible (compiler extensions/builtins for mainstream compilers preferred).
As functions. I wouldn't use macros like #define MIN(X, Y) (((X) < (Y)) ? (X) : (Y)), especially if you plan to deploy your code. Either write your own, use something like standard fmax or fmin, or fix the macro using GCC's typeof (you get typesafety bonus too) in a GCC statement expression:
#define max(a,b) \
({ __typeof__ (a) _a = (a); \
__typeof__ (b) _b = (b); \
_a > _b ? _a : _b; })
Everyone says "oh I know about double evaluation, it's no problem" and a few months down the road, you'll be debugging the silliest problems for hours on end.
Note the use of __typeof__ instead of typeof:
Answer from David Titarenco on Stack OverflowIf you are writing a header file that must work when included in ISO C programs, write
__typeof__instead oftypeof.
Where are
MINandMAXdefined in C, if at all?
They aren't.
What is the best way to implement these, as generically and type safe as possible (compiler extensions/builtins for mainstream compilers preferred).
As functions. I wouldn't use macros like #define MIN(X, Y) (((X) < (Y)) ? (X) : (Y)), especially if you plan to deploy your code. Either write your own, use something like standard fmax or fmin, or fix the macro using GCC's typeof (you get typesafety bonus too) in a GCC statement expression:
#define max(a,b) \
({ __typeof__ (a) _a = (a); \
__typeof__ (b) _b = (b); \
_a > _b ? _a : _b; })
Everyone says "oh I know about double evaluation, it's no problem" and a few months down the road, you'll be debugging the silliest problems for hours on end.
Note the use of __typeof__ instead of typeof:
If you are writing a header file that must work when included in ISO C programs, write
__typeof__instead oftypeof.
It's also provided in the GNU libc (Linux) and FreeBSD versions of sys/param.h, and has the definition provided by dreamlax.
On Debian:
$ uname -sr
Linux 2.6.11
$ cat /etc/debian_version
5.0.2
$ egrep 'MIN\(|MAX\(' /usr/include/sys/param.h
#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))
$ head -n 2 /usr/include/sys/param.h | grep GNU
This file is part of the GNU C Library.
On FreeBSD:
$ uname -sr
FreeBSD 5.5-STABLE
$ egrep 'MIN\(|MAX\(' /usr/include/sys/param.h
#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))
The source repositories are here:
- GNU C Library
- FreeBSD
Using C to Find Min and Max value using Function - Stack Overflow
Add integer functions min and max to C language?
C code to find max and min values: unexpected results
c++ - What are the MAX and MIN in C? #define function - Stack Overflow
Okay, the thing is that you are not updating the data_input after every successive number is inputted. What you are doing is, comparing the last number to 0 or 100, which is logically incorrect. How about you take the first number as input, then after every successive input, compare it with the min and max value. Here is the sample code.
#include <stdio.h>
float max(float num1, float num2){
if(num1 > num2){
return num1;
}
return num2;
}
float min(float num1, float num2){
if(num1 < num2){
return num1;
}
return num2;
}
int main(){
int times, interval;
float mini, maxi, data_Input;
printf("How many number would you like to type in ? : ");
scanf("%d\n",×);
printf("Type in the number: ");
scanf("%f", &data_Input);
// the first number will be minimum and maximum
mini = data_Input;
maxi = data_Input;
for(interval=2; interval<=times; interval++){
printf("\nType in the number: ");
scanf("%f",&data_Input);
// make it a composite if condition
while(data_Input<0 || data_Input>100){
printf("Invalid Input! Please re-enter the number:");
scanf("%f",&data_Input);
}
maxi= max(maxi, data_Input);
mini= min(mini, data_Input);
}
printf("The Lowest Number is %.2f\n", mini);
printf("The Highest Number is %.2f\n", maxi);
return 0;
}
The program checks the last number because you are calling the min and max function out of the for bracelets so instead you can call them inside the for bracelets like:
for(interval=2; interval<=times; interval++){
printf("\nType in the number: ");
scanf("%f",&data_Input);
while(data_Input<0){
printf("Invalid Input! Please re-enter the number:");
scanf("%f",&data_Input);
}
while(data_Input>100){
printf("Invalid Input! Please re-enter the number:");
scanf("%f",&data_Input);
}
maxi= max(data_Input);
mini= min(data_Input);
}
and instead of rewriting the same code you can just ask for the numbers inside the for loop and to initialize your interval to 1 so your main will look like:
int main(){
int times, interval;
float mini, maxi, data_Input;
printf("How many number would you like to type in ? : ");
scanf("%d\n",×);
for(interval=1; interval<=times; interval++){
printf("\nType in the number: ");
scanf("%f",&data_Input);
while(data_Input<0){
printf("Invalid Input! Please re-enter the number:");
scanf("%f",&data_Input);
}
while(data_Input>100){
printf("Invalid Input! Please re-enter the number:");
scanf("%f",&data_Input);
}
maxi= max(data_Input);
mini= min(data_Input);
}
printf("The Lowest Number is %.2f\n", mini);
printf("The Highest Number is %.2f\n", maxi);
return 0;
}
The C programming language is missing library functions min and max for integer types. I am not aware of any argument to not provide them, given virtually every programming language providing them.
Relevance
For floats and doubles, fmin and fmax exists, but not for integer types. Other programming language provide them including C++ by std::min and std::max. Several C libraries provide them too, e.g., Linux, SuperLU, Cairo. Stackoverflow has a question with more then 400 upvotes, indicating that this is a real issue.
Add to C language?
Is it worthwhile to write a paper suggesting the addition of min and max? Or is there a reason that their addition has not already happened?
Hi everyone,
I'm trying to find the maximum and minimum values in a C array, but I'm running into a problem. My code calculates the maximum value correctly, but the minimum value is always a very large negative number, even when all the values in the array are positive.
I've tried initializing the min variable to a large positive number, but it doesn't seem to help.
Here's my code:
#include <stdio.h>
int main(void)
{
int i, sum = 0;
int numbers [5];
int min, max, average;
printf("enter 5 numbers:\n");
for (i = 0; i < 5; i++)
{
scanf("%d", &numbers[i]);
sum += numbers[i];
}
max = numbers[i];
min = numbers[i];
for (i = 0; i < 5 ; i++)
{
if (numbers[i] > max)
{
max = numbers[i];
}
if (numbers[i] < min)
{
min = numbers[i];
}
}
average = (double)sum/5;
printf("Average is %d and sum is %d\n", average, sum);
printf("Max number is %d and the min number is %d\n", max, min);
}Can anyone help me figure out what's going wrong?
Thanks!
It's called the conditional operator (or ternary operator)
#define MIN(a,b) ((a) < (b) ? (a) : (b))
Means:
if ((a) < (b)){
return a;
} else {
return b;
}
So if you would do:
int test = MIN(5,10);
test would be 5
Troubles linking to the wiki page: https://en.wikipedia.org/wiki/Ternary_conditional_operator
#define defines a new preprocessor macro, which in this case place's the MIN code at the point where you place it; with the a and b "variables" being replaced with whatever you gave to the macro as inputs.
#define MIN(a,b) ((a) < (b) ? (a) : (b))
MIN(5,6);
//gets expanded to
((5) < (6) ? (5) : (6))
The actual expression is using the ternary operator to, do return either A or B depending on the evaluation of the expression, you can read more about it here:
http://en.cppreference.com/w/cpp/language/operator_other
Finally, as you marked your question with c++, please consider the non macro max and min functions.
#include <algorithm>
...
int i=std::min(5,6);