understanding memory allocation in C programming language

int Human    ->   4 bytes of memory.


memory bisa terdapat di 2 tempat :   data segment   /   stack.


jika dideklarasikan diluar function ( global var ), masuk ke data segment.
Selama program dijalankan , memory tetap akan digunakan.


stack ->  berisi variabel yang terdapat didalam function.
 sifatnya temporary.
 setelah selesai digunakan, memory dibebaskan dan dapat digunakan oleh program / function lain.


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#include <stdio.h>

int number_of_worker = 10;


void addWorker(){
int stackWorker = 3;  -> memory berada di stack.
number_of_worker += stackWorker;
}


main(){
printf ("there is %i number of worker", number_of_worker);
addWorker();
printf ("there is %i number of worker", number_of_worker);
addWorker();
printf ("there is %i number of worker", number_of_worker);
}




//  result ->  10 13 16


value seperti integer, float, single char tidak perlu manajemen memori yang special. mereka akan otomatis langsung di "free" kan ketika function berakhir / program selesai.


=========
** array

int anArray[10]  // declaring 5 integer of array.  (0-4).

10 integer = 10*4 bytes
     = 40 bytes


c tidak bisa secara otomatis membesarkan ukuran array. harus dilakukan secara manual / menggunakan library 3rd party.


=========
** looping array, random number generator example


#include <stdio.h>
#include <time.h>


#define COUNT 10


main(){
srand (time(NULL));


int anArray[COUNT];
int x;

for (x=0; x<COUNT; x++){
anArray[COUNT] = rand();  // generate rng, input ke anArray
}


for (x=0; x<COUNT; x++){
printf("value an array:  %i\n  %", anArray[x]);
}


}




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string di c adalah kumpulan array character.

char aString[10]="toro"

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null terminator ->>     \0. end of array string. biar bisa di proses secara sempurna ketika di printf %s.



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src code library loca:   /usr/include/string.h