BINARY SEARCH USING C PROGRAM





1. Write a simple code for binary search in c programming language
2. Wap a c program to search an element in an array using binary search

#include<stdio.h>
int main(){

    int a[10],i,n,m,c=0,l,u,mid;

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

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

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

    l=0,u=n-1;
    while(l<=u){
         mid=(l+u)/2;
         if(m==a[mid]){
             c=1;
             break;
         }
         else if(m<a[mid]){
             u=mid-1;
         }
         else
             l=mid+1;
    }
    if(c==0)
         printf("The number is not found.");
    else
         printf("The number is found.");

    return 0;
}

Sample output:
Enter the size of an array: 5
Enter the elements in ascending order: 4 7 8 11 21
Enter the number to be search: 11
The number is found.





43 comments:

  1. not working

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    Replies
    1. you try again

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  2. Hello friend ur program is working sucessfully. Thanks for it.

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  3. cud u put some comments 2 make it easier 2 undrstand

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  4. thanx bro!!! u got a good hand in C!!!!!!!!

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  5. please put some comments

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  6. hey i need a program for graphical representation of binary search in c

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  7. hey can i get a program of queue in c using graphic.c

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  8. it saves our time ....... thanx

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  9. lucky guy

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  10. only works if input array is already sorted

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  11. seocndly ..for m<a[mid]){ u=mid-1; the loop will go infinte

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  12. sorry it wont go infinite..

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  13. I think l < u would be correct

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  14. It is not working......

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  15. can show us it's algorithm as well as flowchart.

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  16. good work

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  17. for searching,array must be sorted

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  18. its realy gud thanx dear

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  19. Could always the input be in ascending order?

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    Replies
    1. Yup it should always be in ascending order.

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  20. nice work bro

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  21. thank you very much. i feel very easy in using 'c' in this blog. so simple and power

    prasad..

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  22. simple huffman algorithm
    #include
    #include
    #include
    void main()
    {
    struct huff
    {
    long int freq,code;
    char data[10];
    }h[50];
    long int n,n1=100,i,j,n2=90,temp;
    char tempc[10];
    clrscr();
    printf("\t\t\tHUFFMAN ALGORITHM\n\n");
    printf("Enter the number of character");
    scanf("%ld",&n);
    for(i=0;i<n;i++)
    {
    printf("Enter the character::");
    scanf("%s",h[i].data);
    printf("Enter the frequency for character %s::", h[i].data);
    scanf("%ld",&h[i].freq);
    }
    for(i=0;i<n-1;i++)
    {
    for(j=1;j<n;j++)
    {
    if(h[i].freq<h[j].freq)
    {
    temp=h[i].freq;
    h[i].freq=h[j].freq;
    h[j].freq=temp;
    strcpy(tempc,h[i].data);
    strcpy(h[i].data,h[j].data);
    strcpy(h[j].data,tempc);
    }
    }
    }
    h[0].code=10;
    h[1].code=11;
    for(i=2;i<n;i++)
    {
    if(i%2==0)
    {
    h[i].code=h[i-2].code+n1;
    n1=n1*10;
    }
    else
    {
    h[i].code=h[i-2].code+n2;
    n2=n2*10;
    }
    }
    printf("Huffman code");
    printf("\nchar\tfreq\tcode");
    for(i=0;i<n;i++)
    {
    printf("\n%s\t%ld\t%ld\n",h[i].data,h[i].freq,h[i].code);
    }
    getch();
    }

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  23. cud u pls do d programs fo findin hcf & lcm ?

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  24. thanx ....but pls put commands....sir

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  25. so many closed braces but only one open brace...how ca it work!!!

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  26. Thankzzzz....!!!!!
    Itzz really very useful 2 meeee......!!!!!!

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  27. Thank you dude its working thanks a lot

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  28. #include
    int main(){

    int a[10],i,n,m,c=0,l,u,mid;
    int j;

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

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

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

    for(j=0;j<n;j++)
    {
    if(m==a[j])
    {
    c=1;
    }

    }


    if(c==0)
    printf("The number is not found.");
    else
    printf("The number is found.");

    return 0;
    }

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  29. what is the diff between linear search and binary search

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    Replies
    1. linear search starts from one value, like the smallest, then iterates through each value to see if it finds what it is searching for, so for example, if looking for the number 19 from 0-40, linear search would go:
      1, 2, 3, 4, 5 etc til it reached 19

      binary search instead, splits the value in 2, until it finds it, so it will do:
      is the number in the middle of 0-40 ? (20, in other words)
      No, then is the value more than, or less than 20?
      If more, then check the middle between 20-40
      If less, check 0-20
      then repeat

      So in this case, that would give us:
      10 (0-20)
      15 (10-20)
      17(or 18) (15-20)
      19, found it!

      The reason this is efficient is that it makes it way faster to search through numbers
      When the sample size is small, it might not make a difference, but when searching through really big numbers, it will show

      For example, find 19000 out of 0-1000000 (one milion)
      500000 (0-1000000)
      250000 (0-500000)
      125000 (0-250000)
      62500 (0-125000)
      31250 (0-62500)
      15625 (0-31250)
      23437 (15625-31250)
      19531 (15625-23437)
      17578 (15625-19531)
      18555 (17578-19531)
      19043 (18555-19531)
      18799 (18555-19043)
      18921 (18799-19043)
      18982 (18921-19043)
      19012 (18982-19043)
      18997 (18982-19012)
      19004 (18997-19012)
      19000 (18997-19004), Found it!

      So in this example it takes 19 steps out of a 1000000 (Milion) numbers
      With linear search it would have taken 19000, in this case
      I think that out of a 1000000000 (Bilion) numbers, it would only require 4-5 more steps to 19.

      So basically, it stays pretty quick even if the numbers increase dramatically.

      Delete
  30. #include

    int main()
    {
    int c, first, last, middle, n, search, array[100];

    printf("Enter number of elements\n");
    scanf("%d",&n);

    printf("Enter %d integers\n", n);

    for ( c = 0 ; c < n ; c++ )
    scanf("%d",&array[c]);

    printf("Enter value to find\n");
    scanf("%d",&search);

    first = 0;
    last = n - 1;
    middle = (first+last)/2;

    while( first <= last )
    {
    if ( array[middle] < search )
    first = middle + 1;
    else if ( array[middle] == search )
    {
    printf("%d found at location %d.\n", search, middle+1);
    break;
    }
    else
    last = middle - 1;

    middle = (first + last)/2;
    }
    if ( first > last )
    printf("Not found! %d is not present in the list.\n", search);

    return 0;
    }

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  31. i am getting it a postion before. ex 1 2 3 4 and i choose to search 3 it show the postion of 3 as 2. help :)

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  32. can i get the logic of the program

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  33. #include
    #include
    int key,A[5],m,i,lb,ub;
    int binary(key,A[],lb,ub)
    {
    if(lb>ub)
    {
    printf("\n Search failed");
    return;
    }
    m=lb+ub/2;
    if(key==A[m])
    {
    printf("\n Match Found and value is %d",key);
    return;
    }
    elseif(key<A[m])
    {
    ub=m-1;
    binary(key,A[],lb,ub);
    }
    else
    {
    lb=m+1;
    binary(key,A[],lb,ub);
    }
    }
    void main()
    {
    clrscr();
    for(i=0;i<5;i++)
    {
    printf("\n Enter the value in array:\n");
    scanf("%d",&A[i])
    }
    printf("\n Enter the value of item to search:\n");
    scanf("%d",&key);
    lb=A[0];
    ub=A[5];
    binary(key,A[],lb,ub);
    getch();
    }

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  34. plz give me the ans for this question


    Given a number.You have to find the binary equivalent of that number first. Your task is to rearrange the 0's and 1's in the binary equivalent found to all the combinations and print all the numbers which form a co-prime with the digit entered.Print nil if no co-prime is found.

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  35. This seems to go infinite unless specified differently, but I may very much be wrong, here is what I am thinking though,

    if (m > n || m < 0 )
    return 0;

    Unless you want to allow the array to contain negative numbers, in that case I assume one would have to put in an algorithm to initiate the smallest number in the array to a variable, then insert that one instead of 0 in the above if statement, one way would be to insert below inside the for loop when scanning for a[i]:

    // once there is exactly 2 elements in the array a[], then initialize min variable as the smallest number
    if (i == 1)
    min = a[0];
    // Now one can compare each iteration to see if a number in the array a[] is smaller
    if (a[i] < min)
    min = a[i];

    So after this, one can use the code above, now in this way:

    if (m > n || m < min )
    return 0;

    But hey, I am actually very very new to this, so please let me know if this even works at all, I am currently learning how to implement binary search, so hopefully my thoughts here are in the ball park at least :)

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