functions c++

[hasib ahmed]

Why Functions are used?


just avoid repetition control structure or more?

[Zeeshanef]

1. Repetition bhi he, mean coding length kam hojati he.

2. function koi khas kaam hota he, jiski bar bar zaroorat parti he, jise call ker kay jawab hasil kar lya jata hay.

3. Code readable aor program reliable hotjata he.

4. Agar future mein us function mein koi changing karni ho to puray program ke code ko nahi dekhna parta bus us function ka code nikal ker modification ker saktay hain.

5. Agar program ka aik function sahi kaam nahi kara to poora program sahi chalay ga, bas us function ko call ker nay se error aai ga, aor is tarhan probelm foran sahi ho jai gi. mean Debug aasan hogi.

6. Agar aap future mein koi aor program develop ker rahay hain, aor aap ko aisa hi koi function chahye jo aap pahlay ker chukay hein to aap simply pahlay program ke function ko copy paste ker dain ge. mean Code Re-usability.

7. Compiler kam time le ga.

Aor bhi faiday hosaktay hain, magar ye wo cheezain theen jo mein ne Software development ke doran mehsoos ki.

[Zeeshanef]

1. Difference between Declaration and Definition:

C++ mein koi function define ker nay se pahlay usay [Declare] ya [prototype] karna parta he. take Compiler ko pata chal ja'e ke koi Function ic name se mojood he jise call kya jasakta he.
For example aap function ke zeryay 2 integer values ko SUM kera chahtay hain, aor value return mein lena chahtay hain.

1. Sab se pahlay aap Function ki prototype dein ge ya usay declare karain gay.

//Declaring the SUM Function
int SUM(int, int);

Uper aap ne SUM function declare kya ab aap Function ko Define karain ge, matlab Function ne kya karna he ya batana hoga:

//Definition of SUM funtion
int SUM(int value1, int value2)
 {
   return value1+value2;
 }

Umeed he aap Declaration aor Definition mein farq samajh gae hongay.

2. Predefined functions ki definition aap Include folder mein mojood head files (*.h) mein dekh saktay hain.

[hasib ahmed]

What are the two methods for calling functions?