Problem Solving Through C (BCA) 1st Sem Previous Year Solved Question Paper 2022

Practice Mode:
3.

Discuss the structure of a C program with the help of an example program.

Explanation

The structure of a C program typically consists of various components, including comments, preprocessor directives, function declarations, and the main function. Let me illustrate this with a simple example program:

 

#include <stdio.h> // Preprocessor directive

// Function declaration

int add(int a, int b);

int main() {

// Variables

int num1, num2, sum;



// Input

printf("Enter two numbers: ");

scanf("%d %d", &num1, &num2);



// Function call

sum = add(num1, num2);

// Output

printf("Sum: %d\n", sum);

return 0; // Return statement

}

// Function definition

int add(int a, int b) {

return a + b;

}

 

  1. Comments:

    • Comments provide human-readable explanations within the code.

    • In the example, ‘//’ is used for single-line comments, and ‘/* */’ is used for multi-line comments.

  2. Preprocessor Directives:

    • These are instructions to the preprocessor that modify the source code before actual compilation.

    • #include <stdio.h> is a common directive to include the standard input/output library.

  3. Function Declaration:

    • Function declarations specify the function's name, return type, and parameter types.

    • In the example, ‘int add(int a, int b); ‘declares the’add’ function.

  4. main() Function:

    • The main() function is the entry point of the program.

    • It contains the program's logic.

    • It returns an integer value (usually 0) to indicate the program's status.

  5. Variables:

    • Variables are used to store and manipulate data.

    • In the example, ‘num1’, ‘num2’, and ‘sum’ are declared as integer variables.

  6. Input and Output:

    • Printf ’ is used to display output to the console.

    • Scanf ’ is used to read input from the user.

  7. Function Definition:

    • The ‘add’ function is defined after the ‘main’ function. It takes two integer parameters and returns their sum.

  8. Return Statement:

    • The ‘return 0; statement in the ‘main’ function indicates that the program executed successfully.

This structure provides a basic framework for C programs. The program starts with the ‘main()’ function, which is where execution begins. Functions are used to modularize code and improve readability and reusability.