C

#include 

switch(expression) {
   case true  :
      break;
   default :
   //
   break;
}

/* A comment
*/

// A comment

double average(int count, ...)
{
 //
}

1 + 1;

#include 
#include 
int main(void)
{
  int *poin = malloc(4);
  free(poin);
}

// https://learn.microsoft.com/en-us/cpp/preprocessor/macros-c-cpp?redirectedfrom=MSDN&view=msvc-170
// https://gcc.gnu.org/onlinedocs/cpp/Macro-Arguments.html
#define min(X, Y)  ((X) < (Y) ? (X) : (Y))
  x = min(a, b);          →  x = ((a) < (b) ? (a) : (b));
  y = min(1, 2);          →  y = ((1) < (2) ? (1) : (2));
  z = min(a + 28, *p);    →  z = ((a + 28) < (*p) ? (a + 28) : (*p));

int pldb = 80766866;

//  If a header file is included within <>, the preprocessor will search a predetermined directory path to locate the header file. If the header file is enclosed in "", the preprocessor will look for the header file in the same directory as the source file.
#include 
#include "stdio.h"

double da = 3.3;
double db = 3.3;
double dc = 3.4;
int result = (int)da + (int)db + (int)dc; //result == 9

#include 
#define height 10
#ifdef
#endif
#if
#else
#ifndef
#undef
#pragma

// C/C++ program to check if a number is
// even or not using goto statement
#include 
using namespace std;
  
// function to check even or not
void checkEvenOrNot(int num)
{
    if (num % 2 == 0)
        goto even; // jump to even
    else
        goto odd; // jump to odd
  
even:
    cout << num << " is evenn";
    return; // return if even
odd:
    cout << num << " is oddn";
}
  
// Driver program to test above function
int main()
{
    int num = 26;
    checkEvenOrNot(num);
    return 0;
}

struct account {
  int account_number;
  char *first_name;
  char *last_name;
  float balance;
};

// A comment

#include 

// Define a public function
double foo(int count)
{
    double  sum = 0.0;

    // Sum all the values bar(1) to bar(count)
    for (int i = 1;  i <= count;  i++)
        sum += bar((double) i);
    return sum;
}
// Symbol Table:
// Symbol name|Type|Scope
// bar|function, double|extern
// x|double|function parameter
// foo|function, double|global
// count|int|function parameter
// sum|double|block local
// i|int|for-loop statement

// Declare an external function
extern double bar(double x);

int i = 4; /* bit pattern equivalent is binary 100 */
int j = i << 2; /* makes it binary 10000, which multiplies the original number by 4 i.e. 16 */

#include 
int i, a[10];
for (i = 0; i < 10; ++i)
  {
  assert(0 <= i && i < 10);
  a[i] = 10-i;
  }
for (i = 0; i < 10; ++i)
  {
  assert(0 <= i && i < 10);
  assert(0 <= a[i] && a[i] < 10);
  a[a[i]] = a[i];
  }

"hello world"

int *ptr;

#include 
int main(void) { printf("%d", 1 ? 1 : 0); }

char character = 'P';

enum Gender {
  Male,
  Female,
};