Unit 1 (Programming in C with Data Structures) – Short Notes (6 Marks Type)

 Q1. Define Algorithm and its properties.

Answer:
An algorithm is a step-by-step finite process to solve a specific problem.

Properties:

1. Definiteness → Steps must be clear.

2. Finiteness → Algorithm must end after finite steps.

3. Input → Zero or more inputs accepted.

4. Output → At least one output produced.

5. Effectiveness → Steps must be simple and feasible.

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Q2. What is a Flowchart? List its advantages.

Answer:
A flowchart is a graphical representation of an algorithm using symbols like oval (Start/End), rectangle (Process), diamond (Decision), parallelogram (I/O).

Advantages:

• Easy to understand.

• Helps in debugging before coding.

• Improves communication between developers.

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Q3. Explain the structure of a C program.

Answer:
Basic structure:

1. Preprocessor directives (#include <stdio.h>)

2. Main function (int main() { ... })

3. Declarations (variables)

4. Statements (logic/code)

5. Return statement (return 0;)

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Q4. Explain Compilation & Execution of a C program.

Answer:
Steps:

1. Writing → Save program as .c file.

2. Compilation → Compiler converts C code → machine code.

3. Linking → Connects with libraries.

4. Execution → Run the program → output is shown.

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Q5. What are Data Types in C?

Answer:
Data types define the kind of data stored in variables.

• Basic: int, float, char, double.

• Derived: arrays, functions, pointers.

• User-defined: structures, union, enum.

• Void: no value.

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Q6. What are Identifiers and Keywords in C?

Answer:

• Identifiers: Names given to variables, functions, etc. (e.g., marks, sum).

• Keywords: Reserved words with special meaning, cannot be used as identifiers (e.g., int, while, return).