Question

Write code that will fill the array a (declared below) with numbers typed in at the keyboard. The numbers will be input five per line, on four lines (although your solution need not depend on how the input numbers are divided into lines). int a[4][5];

Short answer

Answer: To fill a 2-dimensional array of size 4x5 with integers input by the user, use two nested loops to iterate through the rows and columns of the array. Inside the inner loop, take user input for each element using 'scanf()' in C or 'cin' in C++.

Step-by-step solution

Declare and initialize the 2-dimensional array

Declare a 2-dimensional array 'a' of size 4x5 (4 rows and 5 columns). The code already provides this, so nothing needs to be done in this step.

Iterate through the rows and columns

To fill the array, you should use two nested loops (a loop inside another loop). The outer loop iterates over rows from 0 to 3 and inner loop iterates over columns from 0 to 4. Here is a snippet to get an idea of how loops can be used to navigate through the 2-dimensional array: ``` for(int row = 0; row < 4; row++) { for(int col = 0; col < 5; col++) { // Code for taking input and filling the array } } ```

Take user input for each element

Inside the inner loop, use a suitable function, such as 'scanf()' in C or 'cin' in C++, to take user input for each element of the array. For example, in C++: ``` for(int row = 0; row < 4; row++) { for(int col = 0; col < 5; col++) { cin >> a[row][col]; } } ``` In C: ``` for(int row = 0; row < 4; row++) { for(int col = 0; col < 5; col++) { scanf("%d", &a[row][col]); } } ``` After completing step 3, your 2-D array 'a' will be filled with user input values as expected.