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Is it possible to create an array whose length is decided by only user, but not programmer.


error: segmentation fault (core dumped)

Is there any other way?

What I have tried:

#include<stdio.h>
int main()
{
int x;
printf("Enter the length of the character array:");
scanf("%d",x);
int a[x];
return 0;
}
Posted
Updated 25-Apr-21 7:54am
Comments
Patrice T 25-Apr-21 10:07am    
Depend on what size you want.
Dave Kreskowiak 25-Apr-21 10:24am    
Of course, this happens all the time in many applications. You just have to make sure the value entered is a reasonable one before trying to use it to create an array.

You can't define an array's size using a variable. x is a variable, so a[x] isn't allowed. You have to use malloc to allocate the array's memory. Your code shouldn't even compile!

I write C++, which allocates memory differently. But I believe this is what you want:

C
#include <stdio.h>
#include <stdlib.h>

int main()
{
   int x;
   printf("Enter the length of the character array:");
   scanf("%d",x);

   int* a = (int*) malloc(x * sizeof(int));
   return 0;
}
malloc allocates bytes, so you need to allocate enough of them to hold x ints. malloc returns a pointer to the memory that it allocated. That's a void*, so you have to cast it to the type you want (an int*). You can then use a just like an array: a[0]...a[x-1].
 
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You could answer most of your question for yourself by learning the language. See C reference - cppreference.com[^].
 
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