I'm reading the book "Cracking the Coding Interview" which contains several examples of algorithms in C. I'd like to make programs which implement these algorithms and run them as I go along.
One such algorithm is "Min and Max 1" (from the "Big O" chapter):
int min = Integer.MAX_VALUE;
int max = Integer.MIN_VALUE;
for (int x : array) {
if (x < min) min = x;
if (x > max) max = x;
}
I've attempted to 'write a program around this' as follows:
#include<stdio.h>
int array[5] = [1, 3, 2, 5, 4];
int min = Integer.MAX_VALUE;
int max = Integer.MIN_VALUE;
int main(void):
{
for (int x : array) {
if (x < min) min = x;
if (x > max) max = x;
}
printf("The minimum is %i", min)
printf("The maximum is %i", max)
}
However, if I try to compile and run this I get the error: expected identifier before numeric constant int array[5] = [1, 3, 2, 5, 4];
. How would I correctly implement this algorithm for this example input array?
What you mean is the following
#include <stdio.h>
#include <limits.h>
#define N 5
int main( void )
{
int array[N] = { 1, 3, 2, 5, 4 };
int min = INT_MAX;
int max = INT_MIN;
for ( size_t i = 0; i < N; i++ )
{
if ( array[i] < min ) min = array[i];
if ( max < array[i] ) max = array[i];
}
printf( "The minimum is %i\n", min );
printf( "The maximum is %i\n", max );
return 0;
}
The program output is
The minimum is 1
The maximum is 5
As for your program then it contains invalid constructions according to the C grammar.
In C++ the loop can look the same way as you showed.
#include <iostream>
#include <limits>
int main()
{
const size_t N = 5;
int array[N] = { 1, 3, 2, 5, 4 };
int min = std::numeric_limits<int>::max();
int max = std::numeric_limits<int>::min();
for ( int x : array )
{
if ( x < min ) min = x;
if ( max < x ) max = x;
}
std::cout << "The minimum is " << min << std::endl;
std::cout << "The maximum is " << max << std::endl;
return 0;
}
Take into account that there is no sense to declare the array like global.
As for the array definition in C then you can define it either like
int array[5] = { 1, 3, 2, 5, 4 };
(or using some named constant instead of the number 5)
or like
int array[] = { 1, 3, 2, 5, 4 };
In the last case the number of elements is equal to the number of the initializers. Or even you can use the following initialization
int array[] = { [0] = 1, [1] = 3, [2] = 2, [3] = 5, [4] = 4 };
A few issues:
int array[5] = [1, 3, 2, 5, 4];
needs to be int array[] = {1, 3, 2, 5, 4};
The short form for
loop doesn't exist in C. (Are you using a C++11 compiler to compile C code? If so then saving your source file with a .c
extension might be a simple way of putting it into C mode.) Use for (size_t i = 0;
etc. instead and access the array elements by the index i
.
Using min
and max
as variable names is to be discouraged as they frequently appear as macro definitions.
Use C syntax to implement it in C.
{}
, not []
, to define the initial values of arrays. INT_MIN
and INT_MAX
from limits.h
to use minimum and maximum values of int
. int main(void)
. for (int x : array)
is not supported in C. Use one of the supported forms of loops. Here is an implementation in C99:
#include<stdio.h>
#include<limits.h>
int array[5] = {1, 3, 2, 5, 4};
int min = INT_MAX;
int max = INT_MIN;
int main(void)
{
for (size_t i = 0; i < sizeof(array) / sizeof(*array); i++) {
int x = array[i];
if (x < min) min = x;
if (x > max) max = x;
}
printf("The minimum is %i", min);
printf("The maximum is %i", max);
}
Array is initialized inside {} not []
Looks like you copied it from wrong place or you are a java Programmer.
#include<stdio.h>
int a[5] = {1, 3, 2, 5, 4};
int min = Integer.MAX_VALUE;
int max = Integer.MIN_VALUE;
int main(void):
{
for (int x : array) {
if (x < min) min = x;
if (x > max) max = x;
}
printf("The minimum is %i", min)
printf("The maximum is %i", max)
}
This will still give you error if you want i can fix it. I left it so that you can learn this by your own.
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