This document discusses user-defined functions in C programming. It provides examples of functions with and without parameters and return values. It also demonstrates call by value and call by reference methods. The key points covered are: 1) User-defined functions allow programmers to define reusable blocks of code to perform tasks. 2) Functions can receive input from parameters and return outputs through return values. 3) Parameters passed by value are copied into the function, so changes made inside the function do not affect the original variables. 4) Parameters passed by reference allow the function to modify the original variables.

1. C- PROGRAMMING
FUNCTION

2. NOTES

3. System Define function
#include<stdio.h>
#include<conio.h>
#include<math.h>
void main()
{
int num;
float r;
clrscr();
printf(“Enter any non”);
scanf(“%d”,&num);
r=sqrt(num);
printf(“root of %d is %f n”, num,r);
getch();
}
EXTRA

4. NOTES

5. NOTES

6. User Define Function
#include<stdio.h> Parameter and no return value
#include<conio.h>
void add(int, int);
void main()
{
int a,b;
clrscr();
printf(“Enter two numbern”);
scanf(“%d%d”,&a,&b);
printf(“Value of A =%dn”,a);
printf(“Value of B =%dn”,b);
add(a,b);
getch();
} no return
void add(int x, int y)
{ with Parameter
int z;
z=x+y;
printf(“Sum of two no = %dn”,z);
}
EXTRA

7. User Define Function
#include<stdio.h> Parameter and return value
#include<conio.h>
int add(int, int);
void main()
{
int a,b,c;
clrscr();
printf(“Enter two numbern”);
scanf(“%d%d”,&a,&b);
printf(“Value of A =%dn”,a);
printf(“Value of B =%dn”,b);
c=add(a,b);
printf(“Sum of two no = %dn”,c);
getch();
} with return
int add(int x, int y)
{ with parameter
int z;
z=x+y;
return z;
}
EXTRA

8. User Define Function
No #include<stdio.h> Parameter and no return value
#include<conio.h>
void disp();
void main()
{
clrscr();
disp();
getch();
} no return
void disp()
{ no parameter
int a,b,c;
printf(“Enter two numbern”);
scanf(“%d%d”,&a,&b);
printf(“Value of A =%dn”,a);
printf(“Value of B =%dn”,b);
c=a+b;
printf(“Sum of two no = %dn”,c);
getch();
}
EXTRA

9. User Define Function
No Parameter and return value
#include<stdio.h>
#include<conio.h>
int fact();
void main()
{
clrscr();
printf("Factorial %d",fact());
getch();
} with return
int fact()
{ no parameter
int n,f=1;
printf(" Enter any numbern");
scanf("%d",&n);
while(n>=1)
{
f=n*f;
n--;
}
return f;
}
EXTRA

10. User Define Function
Call by value method
#include<stdio.h>
#include<conio.h>
void disp (int , int);
void main()
{
int a,b;
clrscr();
printf(“Enter the Value of a & bn”);
scanf(“%d%d”,&a,&b);
printf(“Value of a before function %dn”,a);
printf(“Value of b before function %dn”,b);
disp(a,b);
printf(“value of a after function %dn”,a);
printf(“Value of b after function %dn”,b);
getch();
}
void disp(int a, int b)
{
a=a+10;
b=b+10;
printf(“Value of a inside function %dn”,a);
printf(“value of b inside function %dn”,b);
}
EXTRA

11. User Define Function
Call by reference method
#include<stdio.h>
#include<conio.h>
void disp (int &, int&);
void main()
{
int a,b;
clrscr();
printf(“Enter the Value of a & bn”);
scanf(“%d%d”,&a,&b);
printf(“Value of a before function %dn”,a);
printf(“Value of b before function %dn”,b);
disp(a,b);
printf(“value of a after function %dn”,a);
printf(“Value of b after function %dn”,b);
getch();
}
void disp(int &a, int &b)
{
a=a+10;
b=b+10;
printf(“Value of a inside function %dn”,a);
printf(“value of b inside function %dn”,b);
}
EXTRA

12. NOTES

13. EXTRA

14. EXTRA

15. EXTRA

16. EXTRA

17. #include<stdio.h>
#include<conio.h>
int table(int,int);
void main()
{
int n,y=1,t;
clrscr();
printf("Enter any non");
scanf("%d",&n);
table(n,y);
getch();
}
int table(int n, int y)
{ int t;
if(y==11)
{
return 0;
}
else
{ t=n*y;
printf("%d*%d=%dn",n,y,t);
table(n,y+1);
}
return t;
}
EXTRA