Functions in C

Functions in C

• 1.
  Functions in C A brief study
• 2.
  Functions • Function isa self-contained block or a sub- program of one or more statements that performs a special task when called.
• 3.
  Example of functions •Hotel management – Front Office – Reservation – Housekeeping – Telephone
• 4.
  Hotel management
• 5.
  Hotel Customer() { House_keeping(); //Function call } House_keeping() //Function definition { Cleans rooms; }
• 6.
  Hotel Customer() //calling function { House_keeping(); //Function call } House_keeping() //called function { Cleans rooms; }
• 7.
  Add two numbers main() { int a,b; int c; printf(“Enter the value of a”); scanf(“%d”,&a); printf(“Enter the value of b”); scanf(“%d”,&b); c=a+b; printf(“Answer is:%d”,c); }
• 8.
  Add two numbersusing functions main() { add(x,y) int a,b; { int c; z=x+y; printf(“Enter the value of a”); printf(“%d”,z); scanf(“%d”,&a); } printf(“Enter the value of b”); scanf(“%d”,&b); add(a,b); }
• 9.
  Arguments/Parameters • Arguments areused mostly in functions. • it can be any input parameter which a function can use to do it's work. • Example: sin(x) sin is a function x is it's argument.
• 10.
  Arguments/Parameters • Actual arguments: • Arguments of calling function • Formal arguments: • Arguments of called function
• 11.
  Add two numbersusing functions main() formal arguments { add(x,y) int a,b; { int c; z=x+y; printf(“Enter the value of a”); printf(“%d”,z); scanf(“%d”,&a); } printf(“Enter the value of b”); scanf(“%d”,&b); add(a,b); //function call } actual arguments
• 12.
  Argument/Parameter list a=2 b=4 add(a,b); add(x,y) x=2 y=4
• 13.
  return statement • functionuses return statement to return the value to the called function. • Exit from the called function. return(expression);
• 14.
  Hotel Customer() //calling function { House_keeping(); //Function call } House_keeping() //called function { Cleans rooms; return 0; }
• 15.
  Hotel Customer() //calling function { Front_office(Money); //Function call } Front_office(Money) //called function { return receipt; }
• 16.
  Types of functions 1. No arguments and no return type 2. No arguments and return type 3. With arguments and no return type 4. With arguments and return type
• 17.
  Passing arguments • Thearguments passed to function can be of two types. 1. Values passed – Call by value 2. Address passed – Call by reference
• 18.
  Call by value •main() { int x=50, y=70; add(x,y); } add(int x1,int y1) { int z1; z1=x1+y1; printf(“%d”,z1); }
• 19.
  Call by reference •main() { int x=50, y=70; add(&x,&y); } add(int *x1,int *y1) { int z1; z1=x1+y1; printf(“%d”,z1); }
• 20.
  Call by reference •Address is passed using symbol ‘&’ value is accessed using symbol ‘*’ x=50 &x=2000 *x=50 y=70 &y=2008 *y=70
• 21.
  Thank you