当我们将一个 int 分配给一个由 2 个 int 组成的数组时会发生什么？

Question

The following code goes through each voter in an election and allows them to rank their candidates by preference: 1, 2, 3 etc.

The code works but I'm just attempting to understand what happens when assigning one int to a 2d array of int s, preferences[voter][rank] = i .

What happens when you assign a single int to a 2 dimensional array of int s?

// Keep querying for votes
    for (int i = 0; i < voter_count; i++)
    {

        // Query for each rank
        for (int j = 0; j < candidate_count; j++)
        {
            string name = get_string("Rank %i: ", j + 1);

            // Record vote, unless it's invalid
            if (!vote(i, j, name))
            {
                printf("Invalid vote.\n");
                return 4;
            }
        }

        printf("\n");
    }

//first loop through ranks gets input from the user... this loop through compares the users
//response to each of the candidates, then locks them in as that rank for that voter
bool vote(int voter, int rank, string name)
{
    for (int i = 0; i < candidate_count; i++)
    {
        if(strcmp(name, candidates[i].name) == 0)
        {
            preferences[voter][rank] = i;
            return true;
        }
    }
    return false;
}

Answer 1

In your code

 preferences[voter][rank] = i;

does not assign an int to a "2 dimensional array of int s" as you mentioned.

Here, preferences[voter][rank] is one element in the array, of type int , and you're assigning an integer value to it.

To elaboate, an array defined like

 int arrayofints[10] = {0};

has 10 elements, of type int , accessed by arrayofints[i] , where 0 <= i <= 9 . So a statement like

 for (int i = 0; i< 10; i++){
     arrayofints[i] = i;
  }

access arrayofints[0] , arrayofints[1] .... respectively and store the value of i into that element. Same goes for multi-dimensional arrays.