0.1 What is a Problem?

A problem is a situation where we know some information, need a particular result, and must find a method to reach that result.

0.2 How Do We Normally Solve a Problem?

Humans often solve simple problems without writing down every step. We understand the situation, compare information, make decisions, and produce an answer. A computer cannot depend on this hidden human understanding.

0.3 What is Programming?

0.4 Why Do We Need a Programming Language?

We communicate with people using languages such as English or Telugu. Computers ultimately operate using machine-level instructions. Programming languages such as C give humans a practical way to describe logic precisely.

0.5 The Basic Input–Process–Output Idea

Many programming problems become easier when you first identify three things: Input, Process, and Output.

0.6 What is an Algorithm?

0.7 Characteristics of a Good Algorithm

0.8 What is a Flowchart?

0.9 What is Pseudocode?

0.10 From Problem to C Program — Add Two Numbers

BEGIN
    READ A, B
    SUM ← A + B
    PRINT SUM
END

#include <stdio.h>

int main()
{
    int a, b, sum;

    scanf("%d %d", &a, &b);

    sum = a + b;

    printf("%d", sum);

    return 0;
}

0.11 Decision Making — Certificate Eligibility

BEGIN
    READ MARKS

    IF MARKS >= 40
        PRINT "Eligible"
    ELSE
        PRINT "Not Eligible"
    END IF
END

#include <stdio.h>

int main()
{
    int marks;

    scanf("%d", &marks);

    if(marks >= 40)
        printf("Eligible");
    else
        printf("Not Eligible");

    return 0;
}

0.12 Repetition — Print Numbers from 1 to 5

Suppose you need to print the numbers 1 to 5. You could write five separate print statements, but the action is repetitive. Programming gives us a better idea: repeat the same type of instruction using a loop.

print 1
print 2
print 3
print 4
print 5

SET i ← 1
WHILE i ≤ 5
    PRINT i
    i ← i + 1
END WHILE

BEGIN
    FOR i ← 1 TO 5
        PRINT i
    END FOR
END

#include <stdio.h>

int main()
{
    for(int i = 1; i <= 5; i++)
        printf("%d ", i);

    return 0;
}

0.13 Algorithm vs Flowchart vs Pseudocode vs Program

0.14 How to Think Before Writing Code

Whenever you see a new programming problem, do not immediately start typing C. First answer these questions.

0.15 What is a Dry Run or Program Tracing?

A dry run means executing the logic manually using sample values. You track how variables change one step at a time before or while checking the program.

A = 10
B = 20

SUM = A + B
SUM = 10 + 20
SUM = 30

Output = 30

0.16 What if the Program Does Not Work?

Finding and correcting such problems is called debugging. Errors are a normal part of programming practice.

0.17 A Simple Problem-Solving Strategy

0.18 Common Beginner Mistakes

0.19 Mini Problem-Solving Practice

For each problem, first identify the Input, Output, and the main logic. Try it yourself before opening the answer.

0.20 Are You Ready to Start C?

You are ready for the next page when these ideas feel understandable. You do not need to be perfect yet.

0.21 Key Takeaway