x^y using recursion

Program:

#include<stdio.h>
int power(int a,int b);
int main()
{
int x,y,ans;
printf("Enter x and y:\n ");
scanf("%d %d",&x,&y);
ans=power(x,y);
printf("%d^%d= %d",x,y,ans);
 return 0;
}
int power(int a,int b)
{
if(b==0)
{
return 1;
}
else
{
return a*power(a,b-1);
}
}

Output:

Fibbonacci series using recursion

Program:

#include<stdio.h>
int fibbonacci(int n);
int main()
{
int i,n;
printf("Enter no. of elements: ");
scanf("%d",&n);
 printf("Fibbonacci of %d:\n " , n);
for(i=0;i<n;i++)
{
      printf("%d ",fibbonacci(i));         
 }
    return 0;
}
int fibbonacci(int n)
{
   if(n == 0)
   {
      return 0;
   }
   else if(n == 1)
   {
      return 1;
   }
   else
   {
      return (fibbonacci(n-1) + fibbonacci(n-2));
   }
}

Output:

Factorial program using recursion

Program:

#include<stdio.h>
long int fact(int n);
int main()
{
int m;
long int f;
printf("Enter Number: ");
scanf("%d",&m);
f=fact(m);
printf("Factorial of %d is : %ld",m,f);
    return 0;
}
long int fact(int n)
{
if(n==1)
{
return 1;
}
else
{
return n*fact(n-1);
}
}

Output:

Reverse string using function

Program:

#include<stdio.h>
#include<string.h>
void reverse(char s[]);
int main()
{
char str[100];
printf("Enter a string: ");
scanf("%s",str);
reverse(str);
printf("%s",str);
    return 0;
}
void reverse(char s[])
{
  int i,j;
  char temp;
  for(i=0,j=strlen(s)-1;i<strlen(s)/2;i++,j--)
  {
  temp=s[i];
  s[i]=s[j];
  s[j]=temp;
  }
}

Output:

Maximum no. from array elements using function

Program:

#include<stdio.h>
int max(int m[],int n);
int main()
{
int a[10],n,i;
printf("Enter No. of elements: ");
scanf("%d",&n);
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
}
    printf("Maximum: %d",max(a,n));
    return 0;
}
int max(int m[],int n)
{
  int max=0,i;
  for(i=0;i<n;i++)
  {
  if(m[i]>max)
  {
         max=m[i];
}
  }
  return max;
}

Output:

Decimal to octal conversion using function

Program:

#include<stdio.h>
void dec2oct(int);
int main()
{
int dec;
printf("Enter Positive Integer Number: ");
scanf("%d",&dec);
dec2oct(dec);
return 0;
}
void dec2oct(int m)
{
    int oct[10],i=0,j;
    while(m>0)
    {
    oct[i]=m%8;
    m=m/8;
    i++;
}
for(j=i-1;j>=0;j--)
{
printf("%d",oct[j]);
}
}

Output:

Decimal to hex conversion using function

Program:

#include<stdio.h>
void dec2hex(int);
int main()
{
int dec;
printf("Enter Positive Integer Number: ");
scanf("%d",&dec);
dec2hex(dec);
return 0;
}
void dec2hex(int m)
{
    int i=0,j;
    char hex[10],store[16]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
    while(m>0)
    {
    hex[i]=store[m%16];
    m=m/16;
    i++;
}
for(j=i-1;j>=0;j--)
{
printf("%c",hex[j]);
}
}

Output:

Decimal to binary conversion using function

Program:

#include<stdio.h>
void dec2bin(int);
int main()
{
int dec;
printf("Enter Positive Integer Number: ");
scanf("%d",&dec);
dec2bin(dec);
return 0;
}
void dec2bin(int m)
{
    int bin[10],i=0,j;
    while(m>0)
    {
    bin[i]=m%2;
    m=m/2;
    i++;
}
for(j=i-1;j>=0;j--)
{
printf("%d",bin[j]);
}
}

Output:

Exchange values using call by reference

Program:

#include<stdio.h>
void exch(int *a,int *b)
{
  int temp;
  temp=*a;
  *a=*b;
  *b=temp;
  printf("Inside Function::\n");
  printf("a=%d b=%d\n",*a,*b);
}
int main()
{
int x,y;
printf("Enter value of x and y: \n");
scanf("%d%d",&x,&y);
exch(&x,&y);
    printf("From main Function::\n");
    printf("x=%d y=%d\n",x,y);
    return 0;
}

Output:

Exchange values using call by value

Program:

#include<stdio.h>
void exch(int a,int b)
{
  int temp;
  temp=a;
  a=b;
  b=temp;
  printf("Inside Function::\n");
  printf("a=%d b=%d\n",a,b);
}
int main()
{
int x,y;
printf("Enter value of x and y: \n");
scanf("%d%d",&x,&y);
exch(x,y);
     printf("From main Function::\n");
     printf("x=%d y=%d\n",x,y);
     return 0;
}

Output:

Maximum of three number using function

Program:

#include<stdio.h>
int maxthree(int,int,int);
int main()
{
int x,y,z,max;
printf("Enter three num: \n");
scanf("%d%d%d",&x,&y,&z);
max=maxthree(x,y,z);
printf("Maximum : %d",max);
    return 0;
}
int maxthree(int a,int b,int c)
{
   return ((a>b)?( ((a>c)?a:c)): ((b>c)?b:c) );
}

Output:

Palindrome number using function

Program:

#include<stdio.h>
int ispalindrome(int num);
int main()
{
int n;
printf("Enter Number: ");
scanf("%d",&n);
if(ispalindrome(n)==1)
{
printf("%d is palindrome",n);
}
else
{
    printf("%d is not palindrome",n);
}
    return 0;
}
int ispalindrome(int num)
{
    int rev=0,temp;
    temp=num;
while(num>0)
{
rev=rev*10+num%10;
num=num/10;
}
if(temp==rev)
{
return 1;
}
else
{
        return 0;
}
}

Output:

Prime number using function

Program:

#include<stdio.h>
int isprime(int num);
int main()
{
int n;
printf("Enter Number: ");
scanf("%d",&n);
if(isprime(n)==1)
{
printf("%d is prime",n);
}
else
{
    printf("%d is not prime",n);
}
    return 0;
}
int isprime(int num)
{
    int i;
for(i=2;i<num;i++)
{
if((num%i)==0)
{
return 0;
}
}
return 1;
}

Output:

Factorial program using function

Program:

#include<stdio.h>
long fact(int n);
int main()
{
int m;
long f;
printf("Enter Number: ");
scanf("%d",&m);
f=fact(m);
printf("Factorial of %d is : %ld",m,f);
 return 0;
}
long fact(int n)
{
int i;
long fact=1;
for(i=1;i<=n;i++)
{
fact=fact*i;
}
return fact;
}

Output:

Sum of first N numbers

Program:

#include<stdio.h>
int add(int);
int main()
{
int n,ans;
printf("Enter n: ");
scanf("%d",&n);
ans=add(n);
printf("Sum : %d",ans);
    return 0;
}
int add(int m)
{
    int sum=0,i;
for(i=1;i<=m;i++)
{
sum=sum+i;
}
return sum;
}

Output: