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Can you subtract characters in C?

#include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, char* argv[]) { char c = '7'; int a = c - '0'; printf("%c\n", c); printf("%d\n", a); return 0; }
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The C programming language made simple

1. How to convert a for loop into a while loop
2. When to use a for loop and when to use a while loop
3. Iterating over an array using pointers
4. How to properly copy text in C
5. How to use malloc to dynamically allocate memory
6. How to declare an array of strings in C
7. How to read a line of text in C
8. String literals and string initializations
9. Iterating over main parts of a matrix
10. Quick introduction to macros
11. Improvements to finding an element in an array
12. printf(MEMORY) | How to print memory to the console
13. What is memory padding
14. 30-second algorithm to check if a number is prime
15. Quick introduction to functions
16. Return value of a function
17. Returning multiple values from a function
18. How to return an array from a function
19. Can you add or subtract two pointers?
20. Can you subtract characters in C?
21. What is typedef?
22. Comparing strings in C
23. How to return a string from a function
24. Creating your own data type in C
25. How to split strings in C (strtok)
26. Useful tips for using printf in C
27. Random number generation in C
28. What are void pointers in C?
29. Memory manipulation functions in C
30. Macros with parameters in C
31. How to return and pass a struct to a function
32. How to properly deal with dynamically allocated memory
33. Difference between arrays and pointers in C
34. What is a static variable?
35. Quirks when it comes to declaring pointers in C
36. What are function pointers in C?
37. Simple technique to understanding all 32 printf functions
38. What are unions in C?
39. Anonymous unions in C
40. Integer type conversions
41. How to use dynamically allocated arrays
42. How to check if a character is a digit
43. Square root and raising to a power in C
44. How to pass arrays to functions in C
45. Memory leaks and how to prevent them
46. How to print in binary
47. Reversing all the bits in an integer
48. The address of an array in C
49. How to parse a string in C (sscanf)
50. The address of an array in C (in-depth)
51. Finding a character inside a string in C
52. The bit shift operators in C
53. The sizeof operator in C
54. The offsetof macro in C
55. Difference between memmove and memcpy
56. Details about the main function
57. Introduction to Enumerations in C
58. Dereferencing in C
59. When to free memory in C
60. Writing to text files in C
61. Reading from text files in C
62. Writing to binary files in C
63. Reading from binary files in C
64. Improvements to reading and writing to text files in C
65. Differences between binary and text files in C
66. How to use fseek in C
67. Integer overflow and underflow explained
68. Infinite loop through integer overflow
69. A quirk about the sizeof operator
70. Short introduction to linked lists in C
71. Iterating over a linked list in C
72. Adding elements to a linked list
73. Deallocating a linked list
74. Adding at the beginning of a linked list
75. Const modifier in C
76. Add after an element in a linked list
77. Sorted linked list
78. Removing an element from a linked list
79. Reversing a linked list
80. Finding loops/cycles in a linked list
81. Counting number of elements (iteratively and recursively) in a linked list
82. Short introduction to doubly linked lists
83. How to find a word inside a sentence in C
84. Iterating over doubly linked lists
85. Deallocating a doubly linked list
86. Add to the beginning of a doubly linked list
87. Add to the end of a doubly linked list
88. Add after a node in a doubly linked list
89. Detecting memory leaks in Visual Studio
90. Removing a node from doubly linked lists
91. Finding a node in a doubly linked list
92. Reversing a doubly linked list
93. getc, getch, getche and getchar in C
94. putc, putch and putchar in C
95. What is the ungetc function?
96. Vulnerabilities of the gets function in C
97. The puts function in C
98. Renaming a file in C
99. Removing a file in C
100. Compile and run C code using Notepad++ (2021)
101. Bitwise operators in C
102. Practical uses of bitwise operations - Implementing a Flag System
103. The conditional operator (or ternary operator) in C
104. How to add all digits of a number in C
105. What are command line arguments (argc and argv)?
106. How to convert strings to numbers in C
107. Parsing a string of numbers in C
108. The switch statement in C
109. More details about the switch statement in C
110. Random numbers in an interval in C
111. Random floating point numbers in C
112. Good practice for freeing memory in C
113. How to parse and validate a number in C
114. Format strings in C
115. Strpbrk and strspn in C
116. What is size_t in C?
117. Concatenating strings in C
118. Replace substrings in C
119. Short introduction to header files in C
120. What are double pointers in C?
121. How to execute another program in C (using exec)
122. What is %n in printf and scanf?
123. Generic data types in C
124. Difference between macros and constants in C
125. Reading/Writing structs to files (aka Serialization)
126. Multidimensional arrays in C
127. Compile and run C code using Visual Studio Code (2021)
128. The fork() function in C
129. Waiting for processes to finish (using the wait function) in C
130. Visualization of a fork call in C
131. Process IDs in C
132. Calling fork multiple times
133. Communicating between processes (using pipes) in C
134. Iterating over neighbours in a multi-dimensional array in C
135. Practical use case for fork and pipe in C
136. "and"/"or" keywords in C
137. Pointer assignment vs strcpy in C
138. Introduction to FIFOs (aka named pipes) in C
139. How to use FIFO files to communicate between processes in C
140. Two way communication between processes (using pipes) in C
141. Executing commands in C
142. Getting exit status code in C
143. Redirecting standard output in C
144. Executing programs vs executing scripts in C
145. Dynamically allocated multi-dimensional arrays in C
146. Why use hexadecimal instead of decimal?
147. Short introduction to signals in C
148. Stopping and continuing the execution of a process (using SIGCONT and SIGSTOP)
149. Background and foreground processes
150. Handling signals
151. Compile and run code using your Android smartphone (2020)
152. Communicating between processes using signals
153. How to send an array through a pipe
154. How to send a string through a pipe
155. Simulating the pipe "|" operator in C
156. Working with multiple pipes
157. Read an array of structs in C
158. Short introduction to threads (pthreads)
159. Difference between processes and threads
160. What are Race Conditions?
161. What is a mutex in C? (pthread_mutex)
162. How to create threads in a loop (pthread_create)
163. Get return value from a thread (pthread_join)
164. How to pass arguments to threads in C
165. Practical example for using threads #1 (Summing numbers from an array)
166. Difference between trylock and lock in C
167. Condition variables in C
168. Signaling for condition variables (pthread_cond_signal vs pthread_cond_broadcast)
169. Practical example for pthread_mutex_trylock
170. What is pthread_exit?
171. Introduction to barriers (pthread_barrier)
172. Practical example to barriers (pthread_barrier)
173. What is pthread_t?
174. What are detached threads?
175. Static initializers in the PTHREAD API
176. Deadlocks in C
177. Recursive mutexes
178. Introduction to semaphores in C
179. Practical example using semaphores (Login Queue)
180. Producer - Consumer Problem in Multi-Threading
181. What are binary semaphores?
182. Difference between Binary Semaphores and Mutexes
183. Getting the value of a semaphore
184. Parallelism vs Concurrency
185. List files in a directory (recursively too!)
186. How to evaluate multiple increments in the same line? (++a + a++ - ++a)
187. Thread Pools in C (using the PTHREAD API)
188. Thread Pools with function pointers in C
189. What is waitpid?
190. Implementing a queue in C
191. Implementing a stack in C
192. Arrays as function parameters in C
193. Visual Studio Code for C/C++ on Linux (2021)
194. How do I run and compile my C code?
195. Intro to recursive functions in C
196. Why are function pointers useful?
197. Calling fork multiple times (part 2) (With a practical example)
198. Sharing functions between files in C
199. Post-increment vs pre-increment in C (a++ vs ++a)

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