Removing white space from a string.

#include<stdio.h>

main()
{
    char str[150];
    int i,j;
    
    printf("Enter a string: ");
    gets(str);
    
    for(i=0; str[i]!='\0'; i++)
    {
        while (!((str[i]>='a'&&str[i]<='z') || (str[i]>='A'&&str[i]<='Z' || str[i]=='\0')))
        {
            for(j=i;str[j]!='\0';++j)
            {
                str[j]=str[j+1];
            }
            str[j]='\0';
        }
    }
    printf("Output String: ");
    puts(str);
}

Find no. of vowels , consonants , digits and white spaces in a string.

#include<stdio.h>

main()
{
    char str[150];
    int i,v,c,ch,d,s,o;
    
    o=v=c=ch=d=s=0;
    
    printf("Enter a string:\n");
    gets(str);
    
    for(i=0;str[i]!='\0';i++)
    {
        if(str[i]=='a' || str[i]=='e' || str[i]=='i' || str[i]=='o' || str[i]=='u' || str[i]=='A' || str[i]=='E' || str[i]=='I' || str[i]=='O' || str[i]=='U')
            ++v;
        else if((str[i]>='a'&& str[i]<='z') || (str[i]>='A'&& str[i]<='Z'))
            ++c;
        else if(str[i]>='0'&&c<='9')
            ++d;
        else if (str[i]==' ')
            ++s;
    }
    printf("Vowels: %d",v);
    printf("\nConsonants: %d",c);
    printf("\nDigits: %d",d);
    printf("\nWhite spaces: %d",s);
}

No. of particular character in a string.

#include <stdio.h>

main()
{
   char c[100],ch;
   int i,count=0;
   
   printf("Enter a string: ");
   gets(c);
   printf("Enter a character to find frequency: ");
   scanf("%c",&ch);
   
   for(i=0;c[i]!='\0';i++)
   {
       if(ch==c[i])
           count++;
   }
   printf("Frequency of %c = %d", ch, count);
}

Prime numbers b/w given interval

/* A C program to display all prime numbers between given interval. */

#include <stdio.h>

main()
{
  int n1, n2, i, j, c;
  
  printf("Enter two numbers :   ");
  
  scanf("%d %d", &n1, &n2);
  printf("Prime numbers between %d and %d are: ", n1, n2);
  for(i=n1+1;i<n2;i++)
  {
      c=0;
      for(j=2;j<=i/2;j++)
      {
        if(i%j==0)
        {
          c=1;
          break;
        }
      }
      if(c==0)
        printf("%d ",i);
  }
}

Prime Number or not

/* A C program to check whether a number is prime or not. */

#include<stdio.h>

main()
{
  int n, i, c=0;
  
  printf("Enter the number to check whether this number is prime or not :  ");
  scanf("%d",&n);
  
  for(i=2;i<=n/2;i++)
  {
      if(n%i==0)
      {
          c=1;
          break;
      }
  }
  if (c==0)
      printf("%d is a prime number.",n);
  else
      printf("%d is not a prime number.",n);
}

Fibonacci series recursive

#include<stdio.h>

void fibonacci(int);

main()
{
    int k,n;
    long int i=0,j=1,f;

    printf("Enter the range of the Fibonacci series: ");
    scanf("%d",&n);

    printf("Fibonacci Series: ");
    printf("%d %d ",0,1);
    fibonacci(n);
}

void fibonacci(int n)
{

   static long int first=0,second=1,sum;

    if(n>0)
 {
         sum = first + second;
         first = second;
         second = sum;
         printf("%ld ",sum);
         fibonacci(n-1);
    }

}

Fibonacci Series

#include<stdio.h>

main()
{
    int k,r;
    int i=1,j=1,f;

    printf("Enter the number range :  ");
    scanf("%d",&r);

    printf("fibonacci series :\n");
    printf("%d\n%d\n",i,j);

    for(k=2;k<r;k++)
 {
         f=i+j;
         i=j;
         j=f;
         printf("%d\n",j);
    }
}

Reverse string

#include<stdio.h>

char* reverse(char[]);

int main()
{

    char str[100],*rev;

    printf("Enter  any string: ");
    scanf("%s",str);

    rev = reverse(str);

    printf("Reversed string is: %s",rev);
}

char* reverse(char str[])
{

    static int i=0;
    static char rev[100];

    if(*str)
 {
         reverse(str+1);
         rev[i++] = *str;
    }

    return rev;
}

Reverse the string without library function

#include<stdio.h>
#include<string.h>

main()
{
 char str[50];
 int i,j,len,temp;
 
 printf("enter the string\n");
 gets(str);
 
 len=strlen(str);
 
 for(i=0,j=len-1;i<=len/2;i++,j--)
 {
  temp=str[i];
  str[i]=str[j];
  str[j]=temp;
 }
 
 printf("reversed string is : %s\n",str);
 
}

Reverse the string

#include<stdio.h>
#include<string.h>

main()
{
 char str[50];
 
 printf("enter the string\n");
 gets(str);
 
 strrev(str);
 
 printf("reversed string is : %s\n",str);
 
}

Swapping without temp variable

#include<stdio.h>

main()
{
  int num1,num2;

  printf("Enter number 1 :  ");
  scanf("%d",&num1);

  printf("Enter number 2 :  ");
  scanf("%d",&num2);

  printf("Before swapping\n");
  printf("number 1 is %d and number 2 is %d\n",num1,num2);

  num1=num1+num2;
  num2=num1-num2;
  num1=num1-num2;

  printf("After swapping \n");
  printf("number 1 is %d and number 2 is %d\n",num1,num2);
}

Swapping using temp variable

#include<stdio.h>

main()
{
  int num1,num2,temp;

  printf("Enter number 1 :  ");
  scanf("%d",&num1);

  printf("Enter number 2 :  ");
  scanf("%d",&num2);

  printf("Before swapping\n");
  printf("number 1 is %d and number 2 is %d\n",num1,num2);

  temp=num1;
  num1=num2;
  num2=temp;

  printf("After swapping \n");
  printf("number 1 is %d and number 2 is %d\n",num1,num2);
}

Linear Search

#include<stdio.h>

main()
{

    int arr[10],i,n,key,c=0;

    printf("Enter the size of an array: ");
    scanf("%d",&n);

    printf("Enter the elements of the array: ");
    for(i=0;i<=n-1;i++)
 {
         scanf("%d",&arr[i]);
    }

    printf("Enter the number to be search: ");
    scanf("%d",&key);
    
 for(i=0;i<=n-1;i++)
 {
         if(arr[i]==key)
   {
             c=1;
             break;
         }
    }
    if(c==0)
         printf("The number is not found");
    else
         printf("The number is found");

    return 0;
}

Heap Sort

#include<stdio.h>
#include<stdlib.h>

main()
{
 int heap[50],i,j,ch,size,loc,par;
    int temp;
 
 printf("enter the size of heap tree\n");
 scanf("%d",&size);
 
 printf("all the elements\n");
 for(i=0;i<size;i++)
 scanf("%d",&heap[i]);
 
 for(i=0;i<size;i++)
 {
  loc=i;
  do
  {
   par=(loc-1)/2;
   if(heap[par]<heap[loc])
   {
    temp=heap[par];
    heap[par]=heap[loc];
    heap[loc]=temp;
   }
   loc=par;
  }while(loc!=0);
 }
 printf("heap tree is \n");
 for(i=0;i<size;i++)
 printf("%d\t",heap[i]);
 
 for(j=size-1;j>=0;j--)
 {
  temp=heap[0];
    heap[0]=heap[j];
    heap[j]=temp;
  par=0;
  do
  {
   ch=2*par+1;
   if(heap[ch]<heap[ch+1]&&ch<j-1)
   ch++;
   if(heap[par]<heap[ch]&&ch<j)
   {
    temp=heap[par];
    heap[par]=heap[ch];
    heap[ch]=temp;
   }
   par=ch;
  }while(ch<j);
 }
 printf("\nsorted array\n");
 for(i=0;i<size;i++)
 printf("%d\t",heap[i]);
}

Binary search

#include<stdio.h>

main()
{

    int arr[100],i,n,key,c=0,first,last,mid;

    printf("Enter the number of element in array :   ");
    scanf("%d",&n);

    printf("Enter the elements in ascending order :   ");
    for(i=0;i<n;i++)
 {
         scanf("%d",&arr[i]);
    }

    printf("Enter the number to be search :   ");
    scanf("%d",&key);

    first=0;
 last=n-1;
    
    while(first<=last)
 {
         mid=(first+last)/2;
         
         if(key==arr[mid])
   {
             c=1;
             break;
         }
         else if(key<arr[mid]){
             last=mid-1;
         }
         else
             first=mid+1;
    }
    if(c==0)
         printf("The number is not found.");
    else
         printf("The number is found.");

    return 0;
}

Binary search ( Recursion )

#include<stdio.h>

int binary(int [],int,int,int,int);

main()
{
 int a[50],i,n,m,first,last,c;
 
 printf("enter the number of elements\n");
 scanf("%d",&n);
 
 printf("enter all elements\n");
 for(i=0;i<n;i++)
 scanf("%d",&a[i]);
 
 printf("enter the number to be searched\n");
 scanf("%d",&m);
 
 first=0;
 last=n-1;
 
 c=binary(a,n,m,first,last);
 
 if(c==0)
 printf("element NOT FOUND\n");
 else
 printf("element found\n");
}

int binary(int a[],int n,int m, int first, int last)
{
 int mid,c=0;
 
 if(first<=last)
 {
   mid=(first+last)/2;
   
   if(m==a[mid])
   {
    c=1;
      }
   else
   {
    if(m<a[mid])
    return binary(a,n,m,first,mid-1);
    else
    return binary(a,n,m,mid+1,last); 
   }
}
 return c;
}

Quick sort on String

/* A c program to perform quick sort on String */

#include<stdio.h>
#include<string.h>
#include<ctype.h>

void quick(char [],int,int);
main()
{
 int first,last,i,j,n;
 char a[50];
 
 printf("enter string\n");
 gets(a);
 n=strlen(a);
 
 quick(a,0,n-1);
 printf("new string\n");
 printf("%s",a);
}
void quick(char a[],int first,int last)
{
 int i,j,pivot,temp;
 
 if(first<last)
 {
  pivot=first;
  i=first;
  j=last;
  
  while(i<j)
  {
   while(tolower(a[i])<=tolower(a[pivot])&&i<last)
   i++;
   while(tolower(a[j])>tolower(a[pivot]))
   j--;
   
   if(i<j)
   {
    temp=a[i];
    a[i]=a[j];
    a[j]=temp;
   }
  }
  temp=a[pivot];
  a[pivot]=a[j];
  a[j]=temp;
  quick(a,first,j-1);
  quick(a,j+1,last);
 }
}

Tower Of Hanoi

#include<stdio.h>
#include<conio.h>

int tower(int,char,char,char);

main()
{
 char source,temp,dest;
 int num;
 
 printf("ENTER THE NUMBER OF DISK FOR 'TOWER OF HANOI'\n");
 scanf("%d",&num);
 
 tower(num,'A','B','C');
 
}
int tower(int num,char source,char temp,char dest)
{
 if(num==1)
 {
  printf("move %d from %c to %c\n\n",num,source,dest);
 }
 else
 {
  tower(num-1,source,dest,temp);
  printf("move %d from %c to %c\n\n",num,source,dest);
  tower(num-1,temp,source,dest);
 }
}