1) What is the first step in problem-solving? A) Writing code B) Debugging C) Understanding the problem D) Optimizing the solution Answer: C 2) Which of these is not a step in the problem-solving process? A) Algorithm development B) Problem analysis C) Random guessing D) Testing and debugging Answer: C 3) What is an algorithm? A) A high-level programming language B) A step-by-step procedure to solve a problem C) A flowchart D) A data structure Answer: B 4) Which of these is the simplest data structure for representing a sequence of elements? A) Dictionary B) List C) Set D) Tuple Answer: B 5) What does a flowchart represent? A) Errors in a program B) A graphical representation of an algorithm C) The final solution to a problem D) A set of Python modules Answer: B 6) What is pseudocode? A) Code written in Python B) Fake code written for fun C) An informal high-level description of an algorithm D) A tool for testing code Answer: C 7) Which of the following tools is NOT commonly used in pr...
ACCESSING THE ELEMENTS OF AN ARRAY
Storing related data items in a single array enables the programmers to develop concise and efficient programs. But there is no single function that can operate on all the elements of an array.
To access all the elements, we must use a loop. That is, we can access all the elements of an array by varying the
value of the subscript into the array. But note that the subscript must be an integral value or an expression that evaluates to an integral value. As shown in above Fig., the
first element of the array marks[10] can be accessed by writing marks[0]. Now to process all the elements of the array, we use a loop as shown in Fig. below.
// Set each element of the array to –1
int i, marks[1 ];
for(i= ;i<1 ;i++)
marks[i] = –1;
Fig: Code to initialize each element of the
array to –1
The code accesses every individual
element of the array and sets its value to –1. In the for loop, first the value of marks[0] is set to –1, then the value of the index (i) is incremented and the next value, that is, marks[1] is set to –1. procedure continues until all the 10 elements of the array are set to –1.
Calculating the Address of Array Elements
You must be wondering how C gets to know where an individual element of an array is located in the memory. The answer is that the array name is a symbolic reference to the address of the first byte of the array. When we use the array name, we are actually referring to the first byte of the array.The subscript or the index represents the offset from the beginning of the array to the element
being referenced. That is, with just the array name and the index, C can calculate the address of any element in the array.
Since an array stores all its data elements in consecutive memory locations, storing just the base address, that is the address of the first element in the array, is sufficient. The address of other data elements can simply be calculated using the base address. The formula to perform this calculation is,
Address of data element, A[k] = BA(A) + w(k – lower_bound)
Here, A is the array, k is the index of the element of which we have to calculate the address, BA is the base address of the array A, and w is the size of one element in memory, for example, size of int is 2.
Example: Given an array int marks[]={99,67,78,56,88,90,34,85}, calculate the address of marks[4] if the base address = 1000.
Solution
We know that storing an integer value requires 2 bytes, therefore, its size is 2 bytes.marks[4] = 1000 + 2(4 – 0)
= 1000 + 2(4) = 1008
Calculating the Length of an Array
The length of an array is given by the number of elements stored in it. The general formula to calculate the length of an array is
Length = upper_bound – lower_bound + 1
where upper_bound is the index of the last element and lower_bound is the index of the first element in the array
Example: Let Age[5] be an array of integers such that Age[0] = 2, Age[1] = 5, Age[2] = 3, Age[3] = 1, Age[4] = 7
Show the memory representation of the array and calculate its length.
Solution
The memory representation of the array Age[5] is given as below.
Here, lower_bound = 0, upper_bound = 4
Therefore, length = 4 – 0 + 1 = 5