How to print the number of elements in an array? - c

Question

How do I make it so I can enter 10 or less elements into an array, and then print the number or elements??
#include <stdio.h>
#define MAX_SIZE 10
int main()
{
int a[MAX_SIZE], i;
printf("Enter up to %d different numbers seperated by spaces: \n", MAX_SIZE);
for(i=0; i < MAX_SIZE; i++)
scanf("%d", &a[i]);
printf("Length: %lu\n", sizeof(MAX_SIZE));
return 0;
}

Answer 1

Please close the for loop while storing data and add another loop before print.

Answer 2

Check this code.
This code takes upto MAX_SIZE [10 here] integer inputs and print the number of elemnts. You can stop the scanf() using CTRL + D [EOF].
IMHO, this is the logical approach to end the input, because if you want to end the input based on some particular number, you can't have that number stored in your array.
#include <stdio.h>
#include <stdlib.h>
#define MAX_SIZE 10
int main()
{
int count = 0;
int arr[MAX_SIZE] = {0, }; //initialize the array
printf("Enter the numbers one by one ==> \n");
for (count = 0; count < MAX_SIZE; count ++)
{
if (scanf("%d", &arr[count]) == EOF)
break;
}
printf("Number of elements into the array %d\n", count);
return 0;
}

Answer 3

Try This
int main()
{
int a[MAX_SIZE], i,count=0;
printf("Enter up to %d different numbers seperated by spaces: \n", MAX_SIZE);
for(i=0; i < MAX_SIZE; i++)
{
scanf("%d", &a[i]);
if(a[i] == -1) // Use any number to break the loop
break; // Break the loop
count++; // Count number of elements
}
printf("Length: %d", count ); //Print number of elements
return 0;
}

Answer 4

You can do it as following, Enter 0 as input where you want to stop entering more elements.
#include <stdio.h>
#define MAX_SIZE 10
int main()
{
int a[MAX_SIZE], i;
int count = 0;
printf("Enter up to %d different numbers seperated by spaces: \n", MAX_SIZE);
for(i=0; i < MAX_SIZE; i++)
{
scanf("%d", &a[i]);
if(!a[i])
break;
count++;
}
printf("Length: %lu\n", count);
return 0;
}

Answer 5

By using any counter variable you can count the number of scanned elements and using that variable you can print also..
int main()
{
int a[MAX_SIZE], i,count=0;
printf("Enter up to %d different numbers seperated by spaces: \n", MAX_SIZE);
for(i=0; i < MAX_SIZE; i++)
{
scanf("%d", &a[i]);
if(a[i] == 0) // Use any number for breaking loop
break; // break the loop
count++; // for Counting number of elements
}
printf("number of scanned elements: %d", count ); //Print number of elements
for(i=0;i<count;i++) // for printing upto scanned numbers
printf("%d\n",a[i]);
return 0;
}
We cant find out that which are scanned elements in one array. Because array can hold garbage values. So, maintain any counter variables for counting the number of elements scanning when you want to scan less than actual array boundary.

Answer 6

Your size will always be MAX_SIZE * sizeof(int); (which is 10 * 4-bytes per int in your case). Test by replacing your printf with:
printf("Length: %d\nsize : MAX_size * sizeof (int): %lu\n", MAX_SIZE, MAX_SIZE * sizeof (int));
output:
Length: 10
size : MAX_SIZE * sizeof (int): 40
Note: The storage size for an integer can very from hardware-to-hardware, so always use sizeof(int) in your computations.
I apologize, I see, you want a way to enter less than 10 and still print the array:
#include <stdio.h>
#define MAX_SIZE 10
int main()
{
int a[MAX_SIZE] = {0};
int i = 0;;
int cnt = 0;
printf("Enter up to %d different numbers seperated by spaces (ctrl+d when done): \n", MAX_SIZE);
while (i < MAX_SIZE)
{
if (scanf("%d%*c", &a[i]) < 1)
break;
i++;
}
cnt = i;
i = 0;
printf ("\nPrinting elements using while loop:\n\n");
while (a[i])
{
printf ("a[%d] = %d\n", i, a[i]);
i++;
}
/* or */
printf ("\nPrinting elements using for loop:\n\n");
for (i = 0; i < cnt; i++)
printf ("a[%d] = %d\n", i, a[i]);
return 0;
}
output:
$ ./bin/arrcnt
Enter up to 10 different numbers seperated by spaces (ctrl+d when done):
1 2 3 4 5
Printing elements using while loop:
a[0] = 1
a[1] = 2
a[2] = 3
a[3] = 4
a[4] = 5
Printing elements using for loop:
a[0] = 1
a[1] = 2
a[2] = 3
a[3] = 4
a[4] = 5
You can either keep a count or by initializing your array to zero, you can use a while loop checking for entries. (note: a '0' entered will not work with the while method, so it is only useful for values > 0) Also note: the use of the format string in scanf to consume the trailing newline. This can save you headaches later.

Answer 7

just add these to your code
for (i = 0; i< MAX_SIZE; i++)
{
printf("%d",a[i]);
}
also add curly brackets to your loop
for (i = 0; i<MAX_SIZE; i++)
{
scanf("%d", &a[i]);
}