CODEWITHSUNDEEP
calgorithm
Sarah De-Paz
Sarah De-Paz

Reputation: 61

In C - counting sequences of 1's

Given a binary number such as "100001111111110000001" where each bit is placed in an array so that the array looks like the following: [1,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,1]

I want to locate the starting index and ending index of any sequence of 1's.

Desired output (reading from right to left):

-starting index = 0

-ending index = 0

(Get this numbers a do something accordingly)

Then:

-starting index = 7

-ending index = 15

(Get this numbers a do something accordingly)

last occurrence -

-starting index = 20

-ending index = 20

(Get this numbers a do something accordingly)

How can I accomplish the desired output in C?

Attaching code I tried:

   for (int i = 0; i< counter; i++) {
    if (bitArray[i] == 0) {
      while (bitArray[i] == 0) {
        startP++;
        endP++;
        i++;
      }
    }
    if(bitArray[i] == 1) {
        startP++;
        while(bitArray[i+1]==1) {
          endP++;
          i++;
        }
    }
    if (endP == startP) {
        //do something
    } else if (endP == (startP + 1)) {
    //do something
    } else if (endP > (startP + 1)) {
    // do something
    }
    endP++;
    startP = endP;
 }

*counter = the len of the array

*endP and startP int, intiliazed.

*bitArray the array as described.

Upvotes: 0

Views: 77

Answers (1)

Anteino
Anteino

Reputation: 1166

I don't know exactly what your code is supposed to do, but if you just want to print start and end indices of sets of 1s, I changed your code a bit to do so:

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

int main()
{
    char msg[64];

    int bitArray[] = {1,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,1};
    int inSet = 0;
    int start;
    int end;

    for (int i = 0; i < sizeof(bitArray); i++) {
        if (bitArray[i] == 1 && inSet == 0) {
            inSet = 1;
            start = i;
        }
        else if(bitArray[i] == 0 && inSet == 1) {
            inSet = 0;
            end = i - 1;
            snprintf(msg, sizeof(msg), "-starting index = %d\n-ending index = %d\n", start, end);
            printf(msg);
        }
    }
    if(inSet == 1)
    {
        end = sizeof(bitArray) - 1;
        snprintf(msg, sizeof(msg), "-starting index = %d\n-ending index = %d\n", start, end);
        printf(msg);
    }
}

Upvotes: 1

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