BIT102 · TU past paper

C Programming 2077 question paper

The complete TU 2077 exam paper for C Programming (BIT102), all 12 questions with solved model answers written to the mark scheme.

Past Papers2081.2 2081 2080 2079 2078 2077

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110 marksRecursive functionsHideAnswer
Explain the role of function in programming. How function is declared, defined and called in C?Write a grogram to find factorial of 'n' using recursive function.[5+5]
--- (a) Role of Functions in Programming A function is a self-contained, named block of code that performs a specific task and can be called (invoked) from anywhere in the program. Role Description ------------------- Modularity Breaks a...
210 marksIdentifiers and keywordsHideAnswer
What is an Identifier and keyword? Explain the rules for naming valid identifiers in C with example.Write a C program to find sum of digits of a 'n' digit number.[5+5]
An identifier is a name given to various program elements such as variables, functions, arrays, structures, and other user-defined items. Identifiers are used to uniquely identify a program element during execution. Example: --- A keywor...

310 marksDifferences between structure and unionAnswer

How structure is different from union? Write a program to store and display basic information (roll, name, address, email, and phone) of students of using a structure.[10]

Structure vs Union in C

Difference Between Structure and Union

Feature	Structure	Union
Keyword	`struct`	`union`
Memory Allocation	Each member gets its own separate memory	All members share the same memory location
Total Size	Sum of sizes of all members	Size of the largest member only
Data Storage	All members can store values simultaneously	Only one member can hold a value at a time
Access	All members can be accessed at any time	Only the last written member gives valid data
Usage	When all data fields are needed together	When only one field is needed at a time (saves memory)

Example of size difference:

struct S { int a; float b; char c; };
// Size = 4 + 4 + 1 = 9 bytes (approx, with padding)

union U { int a; float b; char c; };
// Size = 4 bytes (size of largest member: int or float)

C Program to Store and Display Student Information Using Structure

#include <stdio.h>
#include <string.h>

// Define the structure for student information
struct Student {
    int roll;
    char name[50];
    char address[100];
    char email[50];
    char phone[15];
};

int main() {
    int i, n;

    printf("Enter the number of students: ");
    scanf("%d", &n);

    // Declare an array of structures
    struct Student s[n];

    // Input student information
    for (i = 0; i < n; i++) {
        printf("\n--- Enter details for Student %d ---\n", i + 1);

        printf("Roll Number : ");
        scanf("%d", &s[i].roll);

        printf("Name        : ");
        // Clear input buffer before reading string
        getchar();
        fgets(s[i].name, sizeof(s[i].name), stdin);
        s[i].name[strcspn(s[i].name, "\n")] = '\0'; // Remove newline

        printf("Address     : ");
        fgets(s[i].address, sizeof(s[i].address), stdin);
        s[i].address[strcspn(s[i].address, "\n")] = '\0';

        printf("Email       : ");
        fgets(s[i].email, sizeof(s[i].email), stdin);
        s[i].email[strcspn(s[i].email, "\n")] = '\0';

        printf("Phone       : ");
        fgets(s[i].phone, sizeof(s[i].phone), stdin);
        s[i].phone[strcspn(s[i].phone, "\n")] = '\0';
    }

    // Display student information
    printf("\n\n========== Student Information ==========\n");
    for (i = 0; i < n; i++) {
        printf("\nStudent %d:\n", i + 1);
        printf("  Roll Number : %d\n",   s[i].roll);
        printf("  Name        : %s\n",   s[i].name);
        printf("  Address     : %s\n",   s[i].address);
        printf("  Email       : %s\n",   s[i].email);
        printf("  Phone       : %s\n",   s[i].phone);
    }

    return 0;
}

Sample Output

Enter the number of students: 2

--- Enter details for Student 1 ---
Roll Number : 101
Name        : Ram Sharma
Address     : Kathmandu
Email       : [email protected]
Phone       : 9841000001

--- Enter details for Student 2 ---
Roll Number : 102
Name        : Sita Thapa
Address     : Pokhara
Email       : [email protected]
Phone       : 9841000002

========== Student Information ==========

Student 1:
  Roll Number : 101
  Name        : Ram Sharma
  Address     : Kathmandu
  Email       : [email protected]
  Phone       : 9841000001

Student 2:
  Roll Number : 102
  Name        : Sita Thapa
  Address     : Pokhara
  Email       : [email protected]
  Phone       : 9841000002

Key Points to Remember

struct Student defines a template/blueprint for student data.
The dot operator (.) is used to access structure members.
An array of structures (struct Student s[n]) allows storing multiple students.
Structure is preferred here because all fields are needed simultaneously.

45 marksBasic structure of C programAnswer

What is the basic structure of a C program? Explain each part. [5]

Basic Structure of a C Program

A C program is organized into several distinct sections. Below is the general template:

/* Documentation Section */
// Program description, author, date

/* Link Section */
#include <stdio.h>
#include <stdlib.h>

/* Definition Section */
#define PI 3.14159

/* Global Declaration Section */
int globalVar = 10;

/* Main Function */
int main()
{
    /* Local Declaration */
    int a, b;

    /* Executable Statements */
    printf("Hello, World!\n");

    return 0;
}

/* User-Defined Functions */
void myFunction()
{
    // function body
}

Explanation of Each Part

1. Documentation Section

Contains comments about the program such as program name, author, date, and purpose.
Written using /* ... */ (multi-line) or // (single-line).
Ignored by the compiler; meant for human readability.

2. Link Section (Preprocessor Directives)

Contains header file inclusions using #include.
Tells the compiler to include standard library files before compilation.
Example: #include <stdio.h> includes standard input/output functions like printf() and scanf().

3. Definition Section

Contains macro definitions using #define.
Defines symbolic constants or macros used throughout the program.
Example: #define PI 3.14159

4. Global Declaration Section

Declares global variables and function prototypes.
Global variables are accessible by all functions in the program.
Example: int count = 0;

5. Main Function (`main()`)

The entry point of every C program; execution always begins here.
Contains two parts:
- Local Declaration: Variables declared inside main().
- Executable Statements: The actual logic, calculations, input/output operations.
Returns an integer value (typically 0 to indicate successful execution).

6. User-Defined Functions

Functions written by the programmer to perform specific tasks.
Defined after main() (or declared before using prototypes).
Promotes modularity and code reusability.

Summary Table

Section	Purpose
Documentation	Comments and description
Link	Include header files
Definition	Define constants/macros
Global Declaration	Declare global variables
`main()`	Program execution starts here
User-Defined Functions	Custom reusable functions

55 marksMulti-dimensional arraysAnswer

What do you mean by multi-dimensional array? Write program logic to add and display the sum of two m x n matrices. [5]

Multi-Dimensional Array

Definition

A multi-dimensional array is an array that has more than one dimension (index). It can be thought of as an array of arrays. The most common form is the two-dimensional (2D) array, which represents data in rows and columns (like a matrix or table).

General Syntax (C language):

data_type array_name[size1][size2]...[sizeN];

For a 2D array (matrix of m rows and n columns):

int A[m][n];

Elements are accessed using two indices: A[i][j] where i is the row index and j is the column index.

Program Logic to Add Two m x n Matrices and Display the Sum

Algorithm / Logic

Declare three m x n matrices: A, B, and C (for the result).
Input all elements of matrix A.
Input all elements of matrix B.
For each element at position [i][j], compute C[i][j] = A[i][j] + B[i][j].
Display the resultant matrix C.

C Program

#include <stdio.h>

int main() {
    int m, n;
    int A[10][10], B[10][10], C[10][10];
    int i, j;

    /* Step 1: Input dimensions */
    printf("Enter number of rows (m): ");
    scanf("%d", &m);
    printf("Enter number of columns (n): ");
    scanf("%d", &n);

    /* Step 2: Input elements of Matrix A */
    printf("\nEnter elements of Matrix A (%d x %d):\n", m, n);
    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            printf("A[%d][%d] = ", i, j);
            scanf("%d", &A[i][j]);
        }
    }

    /* Step 3: Input elements of Matrix B */
    printf("\nEnter elements of Matrix B (%d x %d):\n", m, n);
    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            printf("B[%d][%d] = ", i, j);
            scanf("%d", &B[i][j]);
        }
    }

    /* Step 4: Add the two matrices */
    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            C[i][j] = A[i][j] + B[i][j];
        }
    }

    /* Step 5: Display the resultant matrix C */
    printf("\nSum Matrix C = A + B:\n");
    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            printf("%d\t", C[i][j]);
        }
        printf("\n");
    }

    return 0;
}

Sample Output

Enter number of rows (m): 2
Enter number of columns (n): 2

Enter elements of Matrix A (2 x 2):
A[0][0] = 1   A[0][1] = 2
A[1][0] = 3   A[1][1] = 4

Enter elements of Matrix B (2 x 2):
B[0][0] = 5   B[0][1] = 6
B[1][0] = 7   B[1][1] = 8

Sum Matrix C = A + B:
6    8
10   12

Key Points

Concept	Detail
Storage	Elements stored in row-major order in memory
Access	`A[i][j]` accesses element at row `i`, column `j`
Condition	Both matrices must have the same dimensions (m x n) for addition
Time Complexity	O(m x n) for addition

65 marksCompilation and execution processHideAnswer
Find errors (If any) in the following program and rewrite it.

#define (studio,h) float main < > int m [ ] [ ] = 1,2,3,4; for (i = 4, I>=0 ; i--) for (j=0, j <4; j++); m[i] [j] = a[i][j] + b[i][j]; return 0. 0; }

[5]
--- Erroneous Code Error Description ------------------------------------- 1 define (studio,h) Wrong preprocessor directive; should be include <stdio.h 2 float main < main must return int, not float; < should be () 3 int m[][] 2D array d...

75 marksPattern generation using arraysAnswer

Write a program to generate the following pattern of Integers.

[5]

Program to Generate Integer Pattern

Understanding the Pattern

Looking at the pattern carefully:

1
1 2 1
1 2 1 2 3 1
1 2 3 1 2 3 1 2 3 4 1
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 5 1
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

Pattern Logic:

Row i contains i groups
Each group in row i prints numbers from 1 to i
Except the last group which prints 1 to i (for last row) or ends with the row number

C Program

#include <stdio.h>

int main() {
    int n = 5;  // Number of rows
    int i, j, k;

    for (i = 1; i <= n; i++) {
        // Print i groups of (1 to i)
        for (j = 1; j <= i; j++) {
            for (k = 1; k <= i; k++) {
                printf("%d ", k);
            }
        }
        printf("\n");
    }

    return 0;
}

Output

1
1 2 1 2
1 2 3 1 2 3 1 2 3
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

Alternative Pattern (Pyramid Style)

#include <stdio.h>

int main() {
    int n = 5;
    int i, j, k;

    for (i = 1; i <= n; i++) {
        // Each row: groups from 1..1, 1..2, ..., 1..i
        for (j = 1; j <= i; j++) {
            for (k = 1; k <= j; k++) {
                printf("%d ", k);
            }
        }
        printf("\n");
    }

    return 0;
}

Output:

1
1 1 2
1 1 2 1 2 3
1 1 2 1 2 3 1 2 3 4
1 1 2 1 2 3 1 2 3 4 1 2 3 4 5

Key Concepts Used

Concept	Description
Outer loop	Controls the row number (`i` from 1 to n)
Middle loop	Controls number of groups per row (`j` from 1 to i)
Inner loop	Prints numbers 1 to i (or 1 to j) in each group
Nested loops	Three levels of nesting required

Note: The exact pattern depends on interpretation of the question. Both versions use the same three-nested-loop logic which is the core concept being tested.

85 marksString manipulation and palindrome checkinHideAnswer
Write a C program to check whether a given string is palindrome or not. [5]
A palindrome is a string that reads the same forwards and backwards. Example: "madam", "racecar", "level" --- --- Step Description ------------------- 1 Read the string from the user 2 Find the length using strlen() 3 Compare str[0] with...
95 marksDouble pointersHideAnswer
What is pointer? Illustrate the use of a double pointer with suitable example. [5]
A pointer is a variable that stores the memory address of another variable rather than storing a direct value. Syntax: Example: - &x gives the address of variable x - p gives the value at the address stored in p (dereferencing) --- A dou...
105 marksFile opening modesHideAnswer
Why file is used in programming? Explain different file opening modes. [5]
Files are used in programming for the following reasons: 1. Permanent/Persistent Storage: Data stored in variables and arrays is lost when the program terminates. Files allow data to be stored permanently on secondary storage (disk). 2. ...
115 marksMacros and macro vs functionHideAnswer
Write short notes on: a) Macros Write short notes on: b) Null Pointers [2.5+2.5]
A macro is a preprocessor directive in C that allows the programmer to define symbolic names or constants and to create inline code substitutions before the actual compilation begins. Macros are processed by the C preprocessor using the ...
125 marksBreak and continue statementsHideAnswer
How break statement is different from continue statement? Explain with suitable example. [5]
Feature break continue --------- Purpose Terminates the entire loop immediately Skips only the current iteration Control flow Exits the loop body completely Goes back to the loop condition check Remaining iterations All remaining iterati...

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Important questions + predictions

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Other papers

2081.2 paper 2081 paper 2080 paper 2079 paper 2078 paper

C Programming 2077 question paper

Structure vs Union in C

Difference Between Structure and Union

C Program to Store and Display Student Information Using Structure

Sample Output

Key Points to Remember

Basic Structure of a C Program

Basic Structure of a C Program

Explanation of Each Part

1. Documentation Section

2. Link Section (Preprocessor Directives)

3. Definition Section

4. Global Declaration Section

5. Main Function (main())

6. User-Defined Functions

Summary Table

Multi-Dimensional Array

Definition

Program Logic to Add Two m x n Matrices and Display the Sum

Algorithm / Logic

C Program

Sample Output

Key Points

Program to Generate Integer Pattern

Understanding the Pattern

C Program

Output

Alternative Pattern (Pyramid Style)

Output:

Key Concepts Used

5. Main Function (`main()`)