Concepts for C

C is a low-level, procedural programming language known for its efficiency, portability, and versatility. C's structured syntax, powerful standard library, and static typing enable developers to write efficient and portable code for a wide range of applications. However, its manual memory management and pointer arithmetic require careful attention to avoid common pitfalls such as memory leaks and segmentation faults. It is important to note that C does not have many of the built in data structures that come with many of the more higher level programming languages. If a particular feature or data structure is not included, it most likely means that it is not support natively or must be built from the ground up to implement it. For example, C does not have built in sets or classes though you are able to build a similar concept to classes using Structs

• Print Text

  #include <stdio.h>
  
  int main() {
    printf("Hello World!");
    return 0;
  };

• Comments

  // one line comment
  
  /*
  multi 
  line 
  comment
  */

• Variables

  int carCount = 2;
  char name[] = "Joe";
  
  #include <stdbool.h>
  bool isPurple = true;

• Data Types

  int carCount = 2;
  unsigned int age = 15;
  signed short int seaLevel = -10000;
  long long int usBudget = 11000000000;
  unsigned long long int lightSpeed = 11799312874;
  float myGPA = 3.45f;
  double piValue = 3.14159265;
  char lastLetter = 'Z';
  char myName[] = "Joe";
  
  #include <stdbool.h>
  bool isMale = true;

• Math Op

  int carCount = 6;
  int truckCount = 3;
  
  int total = carCount + truckCount;
  printf("%d \n", total);
  
  int subtract = carCount - truckCount;
  printf("%d \n", subtract);
  
  int multiple = carCount * truckCount;
  printf("%d \n", multiple);
  
  int divisible = carCount / truckCount;
  printf("%d \n", divisible);
  
  // performs division and gets remainder which is 0
  int modulo = carCount % truckCount;
  printf("%d \n", modulo);

• Math Functions

  #include <stdio.h>
  #include <math.h>
  #include <stdlib.h>
  #include <time.h>
  
  float power = pow(3.0, 6.0);
  printf("%f \n", power);
  
  float root = sqrt(16.0);
  printf("%f \n", root);
  
  float floorVal = floor(3.14);
  printf("%f \n", power);
  
  float ceilVal = ceil(4.3);
  printf("%f \n",  power);
  
  float roundVal = round(3.4);
  printf("%f \n", roundVal);
  
  // random number from 0 to 100
  srand(time(NULL));
  int ranNum = rand() % 101;
  printf("%d \n", ranNum);

• If/Else

  int carCount = 6;
    
  if (carCount > 3) {
    printf("More than three cars");
  } else if (carCount == 3) {
    printf("Equal to three cars");
  } else {
    printf("Less than three cars");
  }

• Ternary

  int carCount = 3;
  
  char* result = (carCount > 2) ? "Yes" : "No";
  printf("%s", result);
  

• Switch

  int carCount = 3;
  
  switch (carCount) {
    case 1:
      printf("One car");
      break;
    case 2: 
      printf("Two cars");
      break;
    case 3: 
      printf("Three cars");
      break;
    default: 
      printf("More than three");
  }

• Functions

  #include <stdio.h>
  
  int handleCars(int cars, int wheels) {
    total = cars * wheels;
    return total;
  }
  
  int result = handleCars(3, 4);
  printf("%d", result);
  

• Interpolation

  char name[] = "Joe";
  char car[] = "Mazda";
  char result[50];
  
  sprintf(result, "%s drives a %s", name, car);
  printf(result);

• Type Casting

  double squareA(int length) {
    double area = pow(length, 2);
    return area;
  }
  
  char* squareL = "4";
  int convertedVal =  atoi(squareL);
  double area = squareA(convertedVal);
  
  // converted and formatted here
  char result[50];
  snprintf(result, 50, "%f", area);
  printf("%s", result);

• Date and Time

  #include <stdio.h>
  #include <time.h>
  
  // seconds since epoch
  time_t seconds = time(NULL);
  printf("%ld \n", seconds);
    
  struct tm tm = *localtime(&seconds);
    
  // current year
  int year = tm.tm_year + 1900;
  printf("%d \n", year);
    
  // current month
  int month = tm.tm_mon + 1;
  printf("%d \n", month);
    
  // formated date
  char formatted[50];
  sprintf(formatted, "%d/%d/%d", month, tm.tm_mday, year);
  printf("%s", formatted);

• Classes

  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #define MAX_CARS 100
  
  struct Cars {
    char* carList[MAX_CARS];
    int count;
  };
  
  void addCar(struct Cars *cars, const char *car) {
    if (cars->count < MAX_CARS) {
      cars->carList[cars->count] = strdup(car);
      cars->count++;
    } else {
      printf("Maximum limit reached.\n");
    }
  }
  
  void removeFirst(struct Cars *cars) {
    if (cars->count > 0) {
      free(cars->carList[0]);
      for (int i = 1; i < cars->count; i++) {
        cars->carList[i - 1] = cars->carList[i];
      }
      cars->count--;
    } else {
      printf("No cars to remove.\n");
    }
  }
  
  const char* getFirstVal(struct Cars *cars) {
    if (cars->count > 0) {
      return cars->carList[0];
    }
    return "";
  }
  
  int main() {
    struct Cars newList = {{0}, 0};
    addCar(&newList, "Honda");
    addCar(&newList, "Mazda");
    addCar(&newList, "Toyota");
    removeFirst(&newList);
    const char* firstCar = getFirstVal(&newList);
    printf("%s\n", firstCar);
    return 0;
  }

• Inheritance

  // No Native Support or Implementation
  

• Method Overload

  // No Native Support or Implementation
  

• Abstract Class

  // No Native Support or Implementation
  

• Static Class

  // No Native Support or Implementation
  

• Arrays/Lists

  char* names[] = {"Joe", "Alex", "Bob"};
  names[1] = "Tom";
  char* name = names[1];
  int numItems = sizeof(names) / sizeof(names[0]);
  
  printf("%s\n", name);
  printf("%d", numItems);

• Array Methods

  // No Built in methods in C arrays
  
  
  

• Concatenation

  // No Native Support or Implementation
  

• Sort Method

  // No Native Support or Implementation
  

• Objects

  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #define MAX_CAR_BRANDS 10
  #define MAX_NAME_LENGTH 50
  
  struct User {
    char First[MAX_NAME_LENGTH];
    char Last[MAX_NAME_LENGTH];
    int Age;
    int Retired;
    char CarBrands[MAX_CAR_BRANDS][MAX_NAME_LENGTH];
    int carBrandsCount;
  };
  
  void setValues(
    struct User *user,
    const char *first,
    const char *last,
    int age, int retired,
    const char *carBrands[],
    int carBrandsCount
  ) {
    strncpy(user->First, first, MAX_NAME_LENGTH - 1);
    strncpy(user->Last, last, MAX_NAME_LENGTH - 1);
    user->Age = age;
    user->Retired = retired;
    user->carBrandsCount = carBrandsCount;
    for (
      int i = 0; 
      i < carBrandsCount && i < MAX_CAR_BRANDS;
      i++
    ) {
      strncpy(
        user->CarBrands[i],
        carBrands[i],
        MAX_NAME_LENGTH - 1
      );
    }
  }
  
  char* fullName(struct User *user) {
    char *fullName = malloc(MAX_NAME_LENGTH * 2);
    snprintf(
      fullName,
      MAX_NAME_LENGTH * 2,
      "%s %s",
      user->First,
      user->Last
    );
    return fullName;
  }
  
  int main() {
    struct User user;
    const char *carBrands[] = {"Mazda", "Toyota"};
    setValues(&user, "Joe", "Doe", 23, 0, carBrands, 2);
    
    printf("%s\n", user.First);
    printf("%s\n", user.CarBrands[1]);
    printf("%s\n", fullName(&user));
  
    return 0;
  }

• Maps (Key/Value)

  // no built in implementation
  // must be built from scratch
   

• Sets

  // no built in implementation
  

• Stack

  // no built in implementation
  

• Queues

  // no built in implementation
  

• Linked List

  // No Native Support or Implementation
  

• Graphs

  // No Native Support or Implementation
  

• For Loops

  char* names[] = {"Joe", "Alex", "Bob"};
  int numItems = sizeof(names) / sizeof(names[0]);
  
  for (int i = 0; i < numItems; i++) {
    printf("%s\n", names[i]);
  }

• While Loops

  char* carList[] =
    {"Mazda", "Toyota", "Honda"};
  
  int numItems =
    sizeof(carList) / sizeof(carList[0]);
    
  int i = 0;
  while(i < numItems) {
    printf(carList[i]);
    printf("\n");
    i++;
  }

• Loop Breaks

  char* cars[] =
    {"Toyota", "Honda", "Mazda"};
    
  int numItems = sizeof(cars) / sizeof(cars[0]);
  char result[50];
  
  for (int i = 0; i < numItems; i++) {
    if (cars[i] == "Honda") {
      sprintf(result, "Found at index %d", i);
      printf(result);
      break;
    }
    sprintf(result, "Visited index %d\n", i);
    printf(result);
  }

• Recursion

  #include <stdio.h>
  
  int getSum( int arr[], int index ) {
    if (index < 0) {
      return 0;
    }
    return arr[index] + getSum(arr, index-1);
  }
  
  int testArr[] = {1, 2, 4, 5};
  int sum = getSum(testArr, 3);
  printf("%d", sum);

• Regex Words

  // no built in implementation
  

• Regex Numbers

  // no built in implementation
  

• Regex Test

  #include <stdio.h>  
  #include <string.h>  
  #include <stdbool.h>
  
  const char *name = "Bob Lee";  
  const char *search = "Lee";  
    
  char *result = strstr(name, search);  
    
  bool test = result != NULL;
  printf("%d", test);

• Regex Characters

  // no built in implementation