Table of Contents

C PROGRAMMING MIDTERM CHEAT SHEET ............................................................... 2

1. BASIC STRUCTURE OF A C PROGRAM ................................................................................ 2
2. VARIABLES AND DATA TYPES ........................................................................................... 2
3. BASIC I/O OPERATIONS ................................................................................................ 3
4. OPERATORS ............................................................................................................... 4
5. CONTROL STRUCTURES ................................................................................................ 5
6. LOOPS...................................................................................................................... 5
7. ARRAYS ..................................................................................................................... 6
8. FUNCTIONS ............................................................................................................... 7
9. POINTERS .................................................................................................................. 8
10. STRINGS ................................................................................................................. 9
11. MEMORY MANAGEMENT ............................................................................................ 10
12. STRUCTS AND ENUMS ............................................................................................... 11
13. FILE I/O ................................................................................................................ 12
FLOWCHART CHEAT SHEET WITH CLEAR STEPS AND ARROWS ................................................... 14
14. EXAMPLE PROGRAMS FOR PRACTICE ............................................................................. 24
C PROGRAMMING MIDTERM PRACTICE ................................................................... 25
SECTION 1: MULTIPLE-CHOICE QUESTIONS ......................................................................... 25
SECTION 2: SOLUTIONS .................................................................................................. 33
SECTION 3: CODING PRACTICE PROBLEMS .......................................................................... 33
SECTION 4: SOLUTIONS FOR CODING PRACTICE PROBLEMS ..................................................... 34

1
 C Programming Midterm Cheat Sheet

1. Basic Structure of a C Program

In C, every program starts with main, and code is organized with func9ons and
statements within { }.

Example:

#include <stdio.h>

int main() {
// Your code here
return 0;
}

• #include <stdio.h>: Includes standard I/O library, which allows the use of
func9ons like prinG and scanf.

• int main(): The main func9on where program execu9on begins.

• return 0;: Ends the program and returns a value of 0 to the opera9ng system,
indica9ng successful execu9on.

2. Variables and Data Types

Variables store data that the program can manipulate, while data types define the
type of data a variable can hold.

2
• Data Types:

• int: Stores integers (e.g., int num = 5;)

• float: Stores floa9ng-point numbers (e.g., float temp = 25.5;)

• char: Stores single characters (e.g., char leWer = 'A';)

• double: Stores double-precision floa9ng-point numbers for greater

accuracy.

Example:

int age = 20;

float salary = 3000.50;
char grade = 'A';

3. Basic I/O Opera@ons

• Prin@ng Output: Use prinG to display text or variables.

printf("Hello, World!\n");
printf("Age: %d\n", age); // %d for integer

• Reading Input: Use scanf to get user input.

int age;
printf("Enter your age: ");
scanf("%d", &age); // %d matches int type

3
Format Specifiers:

• %d: integer

• %f: float

• %c: character

• %s: string

• %lf: double

4. Operators

• Arithme@c Operators: +, -, *, /, %

• Rela@onal Operators: ==, !=, >, <, >=, <=

• Logical Operators: && (and), || (or), ! (not)

• Assignment Operators: =, +=, -=, *=, /=

Example:

int x = 10;
int y = 5;
int sum = x + y; // Arithmetic
int isEqual = (x == y); // Relational

4
int isPositive = (x > 0 && y > 0); // Logical

5. Control Structures

If-Else: Executes code based on a condi9on.

if (x > y) {
printf("x is greater than y");
} else {
printf("x is not greater than y");
}

Switch: A mul9-branch statement.

int grade = 'A';

switch(grade) {
case 'A':
printf("Excellent");
break;
case 'B':
printf("Good");
break;
default:
printf("Try harder");
}

6. Loops

Loops allow repeated execu9on of a block of code.

• For Loop:

for (int i = 0; i < 10; i++) {

5
 printf("%d ", i);
}

• While Loop:

int i = 0;
while (i < 10) {
printf("%d ", i);
i++;
}

• Do-While Loop (executes at least once):

int i = 0;
do {
printf("%d ", i);
i++;
} while (i < 10);

Loop Control Statements:

• break: Exits the loop.

• con9nue: Skips the current itera9on and con9nues with the next.

7. Arrays

6
Arrays are collec9ons of variables of the same type, stored in a con9guous block
of memory and accessed with an index.

Declara@on:

int numbers[5]; // An array of 5 integers

Ini@aliza@on:

int numbers[5] = {1, 2, 3, 4, 5}; // Array initialized

with values

Accessing Elements:

printf("%d", numbers[0]); // Access the first element

Example: Looping Through an Array:

for(int i = 0; i < 5; i++) {

printf("%d ", numbers[i]);
}

8. Func@ons

Func9ons allow code to be organized into reusable blocks. Func9ons can take
parameters and return values.

Syntax:

return_type function_name(parameters) {
// Function code
return value; // Optional, depends on return_type
}

7
Example:

int add(int a, int b) {

return a + b;
}
int main() {
int sum = add(5, 10);
printf("Sum: %d", sum);
return 0;
}

Types of Func@ons:

• Void Func@on: A func9on that does not return a value.

void printHello() {
printf("Hello, World!");
}

• Func@on with Parameters: Takes input parameters.

int multiply(int x, int y) {

return x * y;
}

9. Pointers

8
Pointers are variables that store the memory address of another variable. They
are powerful tools in C for handling memory and manipula9ng arrays and strings.

Declara@on and Ini@aliza@on:

int x = 10;
int *ptr = &x; // ptr now points to the address of x

Accessing Pointer Values:

• *ptr: Dereferences the pointer to access the value stored at the pointed
address.

• ptr: The pointer itself, which holds an address.

Example:

int x = 10;
int *ptr = &x;
printf("Value of x: %d\n", *ptr); // Output: 10

10. Strings

In C, strings are arrays of characters ending with a null terminator ('\0').

Declara@on and Ini@aliza@on:

char greeting[] = "Hello";

9
Common String Func@ons (from <string.h>):

• strlen(str): Returns the length of the string.

• strcpy(dest, src): Copies src string to dest.

• strcat(dest, src): Concatenates src string to dest.

• strcmp(str1, str2): Compares two strings.

Example:

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

int main() {
char str1[20] = "Hello";
char str2[20];
strcpy(str2, str1);
printf("Copied string: %s\n", str2);
return 0;
}

11. Memory Management

Memory management is essen9al in C for dynamic memory alloca9on and freeing

unused memory.

Func@ons for Dynamic Memory Alloca@on (from <stdlib.h>):

10
• malloc(size): Allocates size bytes of memory and returns a pointer to the
allocated memory.

• calloc(n, size): Allocates memory for an array of n elements of size bytes each
and ini9alizes all bytes to zero.

• realloc(ptr, size): Reallocates memory pointed to by ptr to the new size.

• free(ptr): Frees dynamically allocated memory.

Example:

#include <stdio.h>
#include <stdlib.h>

int main() {
int *arr;
arr = (int *)malloc(5 * sizeof(int)); // Allocate
memory for 5 integers

for (int i = 0; i < 5; i++) {

arr[i] = i + 1;
printf("%d ", arr[i]);
}
free(arr); // Free the allocated memory
return 0;
}

12. Structs and Enums

Structs allow grouping of different data types under a single name.

Declara@on and Usage:

11
struct Person {
char name[50];
int age;
};

int main() {
struct Person person1 = {"Alice", 25};
printf("Name: %s, Age: %d", person1.name,
person1.age);
return 0;
}

Enums are used to assign names to integral constants for beWer readability.

Example:

enum Weekday { Sunday, Monday, Tuesday, Wednesday,

Thursday, Friday, Saturday };
enum Weekday today = Monday;
if (today == Monday) {
printf("Start of the workweek.");
}

Thank you for checking in! Here’s the final sec9on covering File I/O and Example
Programs.

13. File I/O

File input/output (I/O) allows reading from and wri9ng to files, which is essen9al
for data persistence in C programs.

Basic Func@ons for File I/O (from <stdio.h>):

12
• fopen(filename, mode): Opens a file. Common modes are "r" (read), "w"
(write), and "a" (append).

• fprinG(file, format, ...): Writes formaWed output to a file, similar to prinG.

• fscanf(file, format, ...): Reads formaWed input from a file, similar to scanf.

• fclose(file): Closes an opened file.

Example of Wri@ng to a File:

#include <stdio.h>

int main() {
FILE *file = fopen("output.txt", "w");
if (file == NULL) {
printf("Error opening file!");
return 1;
}
fprintf(file, "Hello, file!\n");
fclose(file);
return 0;
}

Example of Reading from a File:

#include <stdio.h>

int main() {
FILE *file = fopen("output.txt", "r");
char line[100];
if (file == NULL) {
printf("Error opening file!");
return 1;
}
while (fgets(line, sizeof(line), file)) {

13
 printf("%s", line);
}
fclose(file);
return 0;
}
Absolutely! Flowcharts with arrows will clarify the steps and help visualize the
logic beWer. Since I can’t directly draw here, I’ll create a descrip9ve format to
simulate each step and direc9on. Here’s how the examples will look with a clearer
flowchart structure.

Flowchart Cheat Sheet with Clear Steps and Arrows

Example 1: Simple Sequence - Sum of Two Numbers

Flowchart:

1. Start ➔

2. Input: Read two numbers (num1 and num2) ➔

3. Process: Calculate sum = num1 + num2 ➔

4. Output: Display sum ➔

5. End

Transla@on in C:

#include <stdio.h>

14
int main() {
int num1, num2, sum;
printf("Enter two numbers: ");
scanf("%d %d", &num1, &num2);

sum = num1 + num2;

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

return 0;
}

Example 2: Decision Making - Check Even or Odd

Flowchart:

1. Start ➔

2. Input: Read a number (num) ➔

3. Decision: Is num % 2 == 0?

• Yes ➔ Output: “Even”

• No ➔ Output: “Odd” ➔

4. End

Transla@on in C:

#include <stdio.h>

int main() {
int num;
printf("Enter a number: ");

15
 scanf("%d", &num);

if (num % 2 == 0) {
printf("Even\n");
} else {
printf("Odd\n");
}

return 0;
}

Example 3: For Loop - Print 1 to 5

Flowchart:

1. Start ➔

2. Ini@alize i = 1 ➔

3. Loop: Is i <= 5?

• Yes ➔ Output i ➔ Increment i++ ➔ Repeat step 3

• No ➔ End

Transla@on in C:

#include <stdio.h>

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

16
 return 0;
}

Example 4: While Loop - Count Down from a Number

Flowchart:

1. Start ➔

2. Input: Read a number (num) ➔

3. Loop: Is num > 0?

• Yes ➔ Output num ➔ Decrement num-- ➔ Repeat step 3

• No ➔ End

Transla@on in C:

#include <stdio.h>

int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);

while (num > 0) {

printf("%d ", num);
num--;
}
printf("\n");

return 0;

17
}

Example 5: Summing Elements of an Array

Flowchart:

1. Start ➔

2. Ini@alize: Set sum = 0 ➔

3. Loop: For i = 0 to i < 5 ➔

• Input: Read arr[i] ➔

• Process: Add arr[i] to sum ➔

• Increment i++ ➔ Repeat step 3

4. Output: Display sum ➔

5. End

Transla@on in C:

#include <stdio.h>

int main() {
int arr[5];
int sum = 0;

printf("Enter 5 numbers:\n");
for (int i = 0; i < 5; i++) {
scanf("%d", &arr[i]);

18
 sum += arr[i];
}

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

return 0;
}

Great! I’ll con9nue with a few more flowchart examples in this format to cover a
wider range of programming concepts. Here we go:

Example 6: FuncRon with Parameters - Product of Two Numbers

Flowchart:

1. Start ➔

2. Input: Read two numbers (num1 and num2) ➔

3. Call Func@on: product(num1, num2) ➔

4. Process in Func@on:

• Mul@ply a * b and return the result ➔

5. Output: Display Product ➔

6. End

Transla@on in C:

#include <stdio.h>

19
int product(int a, int b) {
return a * b;
}

int main() {
int num1, num2;
printf("Enter two numbers: ");
scanf("%d %d", &num1, &num2);

printf("Product: %d\n", product(num1, num2));

return 0;
}

Example 7: Nested If Statements - Grading System

Flowchart:

1. Start ➔

2. Input: Enter score (score) ➔

3. Decision: Is score >= 90?

• Yes ➔ Output “Grade: A” ➔ End

• No ➔ Next Decision: Is score >= 80?

• Yes ➔ Output “Grade: B” ➔ End

• No ➔ Next Decision: Is score >= 70?

• Yes ➔ Output “Grade: C” ➔ End

20
 • No ➔ Output “Grade: F” ➔ End

Transla@on in C:

#include <stdio.h>

int main() {
int score;
printf("Enter your score: ");
scanf("%d", &score);

if (score >= 90) {

printf("Grade: A\n");
} else if (score >= 80) {
printf("Grade: B\n");
} else if (score >= 70) {
printf("Grade: C\n");
} else {
printf("Grade: F\n");
}

return 0;
}

Example 8: Summing Digits of a Number

Flowchart:

1. Start ➔

2. Input: Enter a number (num) ➔

3. Ini@alize: sum = 0 ➔

21
4. Loop: While num > 0

• Process: sum = sum + (num % 10) ➔

• Update: num = num / 10 ➔

5. Output: Display sum ➔

6. End

Transla@on in C:

#include <stdio.h>

int main() {
int num, sum = 0;
printf("Enter a number: ");
scanf("%d", &num);

while (num > 0) {

sum += num % 10;
num /= 10;
}

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

return 0;
}

Example 9: Finding the Maximum of Three Numbers

Flowchart:

1. Start ➔

22
2. Input: Enter three numbers (a, b, c) ➔

3. Decision: Is a >= b and a >= c?

• Yes ➔ Output “Max: a” ➔ End

• No ➔ Next Decision: Is b >= c?

• Yes ➔ Output “Max: b” ➔ End

• No ➔ Output “Max: c” ➔ End

Transla@on in C:

#include <stdio.h>

int main() {
int a, b, c;
printf("Enter three numbers: ");
scanf("%d %d %d", &a, &b, &c);

if (a >= b && a >= c) {

printf("Max: %d\n", a);
} else if (b >= c) {
printf("Max: %d\n", b);
} else {
printf("Max: %d\n", c);
}

return 0;
}

23
14. Example Programs for Prac@ce

Here are a few example programs to prac9ce and reinforce your understanding:

1. Factorial Calcula@on Using Recursion:

int factorial(int n) {
if (n == 0) return 1;
return n * factorial(n - 1);
}

2. Fibonacci Sequence:

int fibonacci(int n) {
if (n <= 1) return n;
return fibonacci(n - 1) + fibonacci(n - 2);
}

3. Average of N Numbers Using Arrays:

#include <stdio.h>

int main() {
int n, sum = 0;
printf("Enter number of elements: ");
scanf("%d", &n);
int arr[n];
for (int i = 0; i < n; i++) {
printf("Enter element %d: ", i + 1);

24
 scanf("%d", &arr[i]);
sum += arr[i];
}
printf("Average: %.2f\n", (float)sum / n);
return 0;
}

C Programming Midterm Prac0ce

Sec@on 1: Mul@ple-Choice Ques@ons

1. What does the following C code output?

int main() { int a = 5; printf("%d", a); return 0; }

• A. 4

• B. 5

• C. 6

• D. Undefined

2. Which data type can hold a single character?

• A. int

• B. float

25
 • C. char

• D. double

3. What is the output of the following code?

int a = 3;
int b = 2;
printf("%d", a * b);

• A. 6

• B. 5

• C. 3

• D. Undefined

4. What is the result of the following condi@on?

int a = 5;
int b = 10;
if (a > b) { printf("True"); } else
{ printf("False"); }

• A. True

• B. False

• C. Undefined

• D. Error

26
5. What will the following loop print?

for (int i = 0; i < 3; i++) {

printf("%d ", i);
}

• A. 0 1 2

• B. 0 1 2 3

• C. 1 2 3

• D. 0 1
6. What is the output of the following code?

int a = 10;
int b = 20;
if (a > b) {
printf("A is greater\n");
} else {
printf("B is greater\n");
}

• A. A is greater

• B. B is greater

• C. Error

• D. None of the above

27
7. Which of the following operators is used to access the value stored at the
memory address held by a pointer?

• A. *

• B. &

• C. ->

• D. .

8. Which of the following correctly declares a pointer to an integer?

• A. int p;

• B. int *p;

• C. *int p;

• D. int &p;

9. What is the output of the following code?

int arr[3] = {1, 2, 3};

printf("%d", arr[1]);

• A. 1

• B. 2

28
• C. 3

• D. Undefined

10. Which func@on is used to find the length of a string in C?

• A. strcpy()

• B. strlen()

• C. strcat()

• D. strcmp()

11. What will the following code print?

int x = 5;
int y = 10;
int z = x + y;
printf("%d", z);

• A. 5

• B. 10

• C. 15

• D. Error

12. Which of the following is the correct syntax for an if statement?

29
• A. if condi9on {}

• B. if (condi9on) {}

• C. if [condi9on] {}

• D. if {condi9on}

13. Which library must be included to use the prinG func@on?

• A. #include <stdlib.h>

• B. #include <math.h>

• C. #include <stdio.h>

• D. #include <string.h>

14. What does malloc func@on do?

• A. Allocates memory dynamically

• B. Frees memory

• C. Copies memory

• D. Checks memory size

30
15. Which of these are valid data types in C?

• A. string

• B. int

• C. double

• D. Both B and C

15. What is the output of the following code?

int i = 0;
while (i < 3) {
printf("%d ", i);
i++;
}

• A. 0 1 2

• B. 1 2 3

• C. 0 1 2 3

• D. Infinite loop

16. Which of the following is a logical operator in C?

• A. &&

• B. ||

31
• C. !

• D. All of the above

17. Which format specifier is used to print a float value?

• A. %d

• B. %f

• C. %c

• D. %s

18. What will be the output of the following code?

int a = 10, b = 5;
printf("%d", a % b);

• A. 0

• B. 1

• C. 2

• D. 5

19.. What does free() do?

32
• A. Allocates memory

• B. Deallocates memory

• C. Copies memory

• D. Resizes memory

Sec@on 2: Solu@ons

Answers for MulRple-Choice QuesRons

1. B 11.C
2. C 12.B
3. A 13.C
4. B 14.A
5. A 15.D
6. B 16.A
7. A 17.D
8. B 18.B
9. B 19.A
10.B 20.B

Sec@on 3: Coding Prac@ce Problems

1. Write a C program that prints all even numbers from 1 to 50.

33
 2. Translate the following flowchart into a C program:

Start → Input a number → Check if it’s even or odd → Print result → End.

3. Create a func@on in C that takes two integers and returns their sum.

4. Write a C program to calculate the factorial of a given number.

5. Translate a flowchart that prints the first 10 numbers in the Fibonacci

sequence into C.

6. Implement a C program that finds the largest number in an array of

integers.

7. Translate a flowchart that takes user input for a number and prints “Even”
or “Odd” into C.

8. Write a C program that reverses an array of integers.

9. Create a C program that calculates the average of N numbers provided by

the user.

10. Translate a flowchart for a simple ATM simulator (Deposit, Withdraw,

Check Balance) into C.

Sec@on 4: Solu@ons for Coding Prac@ce Problems

1. Solu@on for Prin@ng Even Numbers from 1 to 50

#include <stdio.h>
int main() {
for(int i = 1; i <= 50; i++) {
if(i % 2 == 0) {

34
 printf("%d ", i);
}
}
return 0;
}

2. Flowchart to C - Even or Odd Check

#include <stdio.h>
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
if(num % 2 == 0)
printf("Even\n");
else
printf("Odd\n");
return 0;
}

3. Func@on to Sum Two Integers

#include <stdio.h>
int sum(int a, int b) {
return a + b;
}
int main() {
int a = 5, b = 3;
printf("Sum: %d\n", sum(a, b));
return 0;
}

4. Factorial Calcula@on

#include <stdio.h>
int factorial(int n) {
int result = 1;
for(int i = 1; i <= n; i++)
result *= i;

35
 return result;
}
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
printf("Factorial: %d\n", factorial(num));
return 0;
}

5. Fibonacci Sequence for First 10 Numbers

#include <stdio.h>
int main() {
int n1 = 0, n2 = 1, n3;
printf("%d %d ", n1, n2);
for(int i = 2; i < 10; ++i) {
n3 = n1 + n2;
printf("%d ", n3);
n1 = n2;
n2 = n3;
}
return 0;
}

6. Finding Largest in Array

#include <stdio.h>
int main() {
int arr[] = {1, 2, 3, 8, 5};
int max = arr[0];
for(int i = 1; i < 5; i++) {
if(arr[i] > max) {
max = arr[i];
}
}
printf("Largest: %d\n", max);
return 0;
}

36
7. Even or Odd Check Using Flowchart Transla@on

#include <stdio.h>
int main() {
int number;
printf("Enter a number: ");
scanf("%d", &number);

if (number % 2 == 0)
printf("Even\n");
else
printf("Odd\n");

return 0;
}

8. Reversing an Array of Integers

#include <stdio.h>

int main() {
int arr[5] = {1, 2, 3, 4, 5};
int n = 5;

printf("Original Array: ");

for (int i = 0; i < n; i++) {
printf("%d ", arr[i]);
}

printf("\nReversed Array: ");

for (int i = n - 1; i >= 0; i--) {
printf("%d ", arr[i]);
}

return 0;
}

37
9. Calcula@ng the Average of N Numbers Provided by the User

#include <stdio.h>

int main() {
int n, sum = 0;
printf("Enter the number of elements: ");
scanf("%d", &n);

int numbers[n];
for (int i = 0; i < n; i++) {
printf("Enter number %d: ", i + 1);
scanf("%d", &numbers[i]);
sum += numbers[i];
}

float average = (float)sum / n;

printf("Average: %.2f\n", average);

return 0;
}

10. ATM Simulator (Deposit, Withdraw, Check Balance)

#include <stdio.h>

int main() {
int balance = 100; // Starting balance
int choice, amount;

do {
printf("\nATM Menu:\n");
printf("1. Check Balance\n");
printf("2. Deposit\n");
printf("3. Withdraw\n");
printf("4. Exit\n");
printf("Enter your choice: ");
scanf("%d", &choice);

38
 switch (choice) {
case 1:
printf("Balance: $%d\n", balance);
break;
case 2:
printf("Enter amount to deposit: ");
scanf("%d", &amount);
balance += amount;
printf("Deposit successful! New
balance: $%d\n", balance);
break;
case 3:
printf("Enter amount to withdraw: ");
scanf("%d", &amount);
if (amount <= balance) {
balance -= amount;
printf("Withdrawal successful! New
balance: $%d\n", balance);
} else {
printf("Insufficient funds.\n");
}
break;
case 4:
printf("Exiting ATM.\n");
break;
default:
printf("Invalid choice. Please try
again.\n");
}
} while (choice != 4);

return 0;
}

39