Ch 4Introduction to Problem Solving — Class 11 Computer Science, concept-first.

Computers surround us today because they let us finish routine tasks faster and with fewer errors. A familiar illustration is booking a train ticket online.

Solving a problem rarely happens in one leap; it usually unfolds as a series of steps. A real-life analogy makes this clear. Imagine that a vehicle you are driving begins to make an odd noise.

The first step of problem solving is to understand the problem thoroughly before attempting any solution.

Before a single line of program code is written, a solution to the problem must be devised. That solution, expressed in natural language as a set of steps, is called an algorithm.

Once the algorithm is finalised, it must be converted into a form the computer can act upon — that conversion is coding.

Writing the program is not the end of the journey — the program must now be tested against various parameters to confirm it truly solves the problem. A program passes muster only when it:

Everyday life is full of activities we complete by following a fixed sequence of steps — getting ready for school, making breakfast, riding a bicycle, wearing a tie, solving a puzzle.

A programmer writes a program to make the computer perform certain tasks, and the computer then follows the steps written in that program code.

Software designers and programmers use their algorithmic thinking skills to analyse a problem and identify the logical steps that must be followed to reach a solution.

A flowchart is a visual representation of an algorithm: a diagram made up of boxes, diamonds and other shapes connected by arrows.

A pseudocode (pronounced Soo-doh-kohd) is the second common way of representing an algorithm. It is a non-formal language that helps programmers write algorithms: a detailed description of the instruc…

The flow of control is the order in which the events of an algorithm unfold — exactly what a flowchart's arrows depict.

Look back at Examples 4.3 (sum of two numbers) and 4.4 (area and perimeter of a rectangle): in both, the statements execute one after another, from the first line to the last, with nothing skipped and…

Decision-making enters an algorithm the moment more than one path is possible. Selection is the flow-of-control construct that chooses among alternatives based on a condition.

When giving directions, we naturally speak in repetitions: "walk 50 steps then turn right", or "walk till the next crossing, then take a right turn". Other everyday examples of the same pattern:

Imagine a banking software that does not work correctly — say the online money-transfer module is programmed wrongly and credits only half the transacted amount into the account, or worse, debits the…

A problem solvable by computer can usually be approached in more than one way — which means more than one algorithm can exist for it.

Once an algorithm is finalised, it must be coded in a high-level programming language of the programmer's choosing: the ordered set of instructions is written in that language, following its syntax.

Some problems are complex in the sense that their solution is not directly derivable — no single algorithm obviously produces it.

- Problem solving is the process of identifying a problem, developing an algorithm for it, and implementing that algorithm as a computer program.