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show_types

purpose: show some basic types and type operations

args: (out) result - ptr to the result of this func

returns: nothing

*****************************************************************************/void show_types(int *result)

{

/* vars */

int number = 0; /* whole signed num register size */

char letter = 'c'; /* whole signed num 1 byte size */

char *string = "hello"; /* ptr to null-term char array */

char buffer[50]; /* ptr to a buffer of 50 bytes */

int array[3] = {1,2,3}; /* ptr to 3 member array of ints */

float fraction = 3.14; /* real num 4 byte size */

double bigfrac = 1.41; /* real num 8 byte size */

unsigned long num = 22; /* whole unsigned num 4 byte size */signed short num2 = -17; /* whole signed num 2 byte size */

int multi_arr[5][2]; /* ptr to 5 arrays of 2 ints */

static int times_called = 0;

/* var operations */

number = (int)letter + 1; /* number now equals 'd' which is 0x64 */

number++; /* number now equals 'e' which is 0x65 */

number = number % 2; /* number now equals 1 (modulus) */

letter -= 2; /* letter now equals 'a' which is 0x61 */

num = num ^ 0x55555555; /* num is xored with 0x55555555 */

string[0] = 'j'; /* string now points to "jello", 0 is first pos */

*(string+4) = 'y'; /* string now points to "jelly" */

string = &letter; /* string now points to letter, which is 'a' */

fraction = 2 * 2.3 / 1.2; /* fraction now equals 3.83333 */

num = (~0x00) & 0x03 | (1

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if ((0 == age) && (age != 1)) return; /* just born */

/* if-else statement */

if ((age < 18) || !(age

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glock.magazine_size++;

gun_ptr->magazine_size = glock.magazine_size + 13;

today++; /* today is actually int */

}

Dynamic Memory

#include

#define NULL (0)

/*****************************************************************************

name: show_dynamic_mem

purpose: show usage of dynamic memory allocation

args: (in) size - size of buffer to use (in bytes)

(in) elements - num of elements to hold

returns: 0 on success, -1 on failure

*****************************************************************************/

int show_dynamic_mem(int size, int elements){

/* vars */

char *buffer = NULL;

int *dyn_int_array = NULL;

/* allocate buffer of size bytes */

buffer = malloc(size);

if (NULL == buffer) return -1;

/* allocate dynamic array of elements ints */

dyn_int_array = malloc(elements * sizeof(int));

if (NULL == dyn_int_array)

{

free(buffer);

return -1;

}

do_something(buffer, dyn_int_array);

/* cleanup */

free(buffer);free(dyn_int_array);

return 0;

}

Standard IO

#include

#define NULL (0)

/*****************************************************************************

name: show_stdiopurpose: show usage of standard input / output

args: (in) filename - name of file to work with

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returns: 0 on success, -1 on failure

*****************************************************************************/

int show_stdio(char *filename)

{

/* vars */

FILE *input = NULL;

unsigned long dword = 0;int items_read = 0;

/* open the file in binary mode for read only */

input = fopen(filename, "rb");

robert

adhiif (NULL == input)

{

printf("cant open %s\n",filename);

return -1;

}

/* read dwords from the file */

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adhi

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while (!feof(input))

{

items_read = fread(&dword, sizeof(dword), 1, input);

if (1 == items_read) printf("read from %s the dword %08x\n",filename,dword);

else break;

}/* cleanup */

fclose(input);

return 0;

}

Preprocessor and H Files

/*****************************************************************************

name: h_file_example

purpose: demonstrate usage of an h file and the preprocessor

*****************************************************************************/#ifndef __H_FILE_EXAMPLE__

#define __H_FILE_EXAMPLE__

#include "another_h_file.h"

/* defines */

#define NULL (0)

#define TRUE (1)

#define FALSE (0)

#define GREETING "hello world"

/* macros */

abram#define max(A,B) ((A)>(B)?(A):(B))extern int global_in_c; /* declare a global defined in matching c file *//*****************************************************************************

name: show_types

purpose: show some basic types and type operations

args: (out) result - ptr to the result of this func

returns: nothing*****************************************************************************/

void show_types(int *result);

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/*****************************************************************************

name: show_flow

purpose: show some basic flow blocks

args: none

returns: total score

*****************************************************************************/int show_flow();

#endif /*__H_FILE_EXAMPLE__*/

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