Can I define and assign an integer array at the same time like we do with the string array?

Question

Here is how I defined and assigned a string array at the same time

#include <stdio.h>
#include <cs50.h>
#include <string.h>

int main()
{
    string word = get_string("Enter a Word;");

    for(int i = 0; i<strlen(word); i++)
    {
        printf("%c\n",word[i]);
    }
}

Now I want to apply the same technique for taking integer values from user

#include <stdio.h>
#include <cs50.h>

int main()
{
    int scores[] = get_int("Enter score:");
    int len = sizeof(scores)/sizeof(int);

    for(int i = 0; i<len; i++)
    {
        printf("%i\n", scores[i]);
    }
}

But the code doesn't get compiled and compiler says like this:

IntArray.c:5:9: error: array initializer must be an initializer list or wide string literal
    int scores[] = get_int("Enter integer:");
        ^
1 error generated.
make: *** [<builtin>: IntArray] Error 1

I know we have a for loop for that solution, which goes like this: That's why I have to keep using for loop, which looks like this:

#include <stdio.h>
#include <cs50.h>

int main()
{
    int scores[3];

    for(int I = 0; I<3; I++)
    {
        score[I] = get_int("Enter score: ");
    }

    for(int j =0; j<3; j++)
    {
        printf("%I\n", scores[j]);
    }
}

My question is can I define and assign the integer array at the same time?

I tried to define and assign an integer array at the same time as we do with the single string, but I couldn't.

Answer 1

Can I define and assign an integer array at the same time like we do with the string array?

string word is not an array. That object is of a CS50 type string, which is a pointer, that points to an array of char.
Arrays are not pointers.
Pointers are not arrays.

Code can create similar code to define an int pointer ...

// string word = get_string("Enter a Word;");
int *ints = get_ints("Enter ints;");

... and use a special value, like INT_MIN, to denote the end of the array of ints. Of course then INT_MIN is not available as a value to read. This is analogous to C strings, which uses a special value, the null character to signify the end of the array.

---

My question is can I define and assign the integer array at the same time?

Yes.

See @M.M comment.

int scores[] = { get_int("Enter score:"), get_int("Enter score:"), get_int("Enter score:") };

This obliges that the array size is determined before getting the data.

---

Code could read the ints into some collection of data, then use the int count to define a variable length array (VLA). But VLAs may not be initialized. They could be assigned later.

some_tbd_data_collection_type data = 0;
unsigned n = get_ints(&data);
int a[n];
for (unsigned i = 0; i < n; i++) {
  a[i] = get_int(&data, i);
}
data_free(&data); 

Answer 2

Building on this earlier answer. The function read_ints reads integers until it reads end_of_list, after which it returns.

void read_ints(Array *a, int end_of_list)
{
    int current;
    while(1){
        scanf("%d",&current);
        if(current == end_of_list) return;
        insertArray(a,current);
    }
}
int main()
{
    Array a;
    initArray(&a, 5);
    printf("Enter numbers:");
    read_ints(&a,-1);

    for(int i=0; i<a.used; i++) printf("%d ", a.array[i]);
    return 0;
}

Answer 3

Here is how I defined and assigned a string array at the same time

This statement is incorrect. In the line

string word = get_string("Enter a Word;");

the variable word is not an array. In particular, the data type string is not an array, but rather a reference ("a pointer") to an array. You will learn this in week 4 of CS50.

What really happens is that the function get_string creates an array based on user input and returns a reference to this newly created array. You then store this reference in the variable word. So you are creating a copy of the reference, not a copy of the array itself.

Here is an example program for demonstration purposes:

#include <cs50.h>
#include <stdio.h>

int main( void )
{
    string word1 = get_string( "Enter a word: " );
    string word2 = word1;
    word2[0] = 'J';

    printf( "\nContent of strings:\n" );
    printf( "word1: %s\n", word1 );
    printf( "word2: %s\n", word2 );
}

In the program above, if the user enters Test, then the line

string word2 = word1;

will not make a copy of the array containing the characters Test, but merely make a copy of the reference to the array. Afterwards, you will have two variables referencing the same array.

If you then modify the first character of the array using

word2[0] = 'J';

you will be modifying the array referenced by word1 and word2. Therefore, the lines

printf( "word1: %s\n", word1 );
printf( "word2: %s\n", word2 );

will not output the original input Test, but will both output Jest.

For this reason, half of your question does not make sense, because initializing an array cannot be compared with initializing a reference ("a pointer") to an array.

My question is can I define and assign the integer array at the same time?

The line

int scores[] = get_int("Enter score:");

will not work.

On the other hand,

int scores[] = { get_int("Enter score:") };

will work, but this is probably not what you want, because it will only create an array of size 1 and calling the function get_int will only ask the user for a single int.

If you want to ask the user for several int values, then you will have to call the function get_int multiple times, for example like this:

int scores[] = {
    get_int( "Enter first score: "),
    get_int( "Enter second score: "),
    get_int( "Enter third score: ")
};

However, this solution is not ideal, especially if you later want to change your program to have more than 3 inputs. Therefore, not initializing the array in the declaration and using a loop instead (as you do in your last code snippet) would probably be the better solution.