All_Indices_of_Number.cpp

/*
Problem:

Given an array of length N and an integer x, you need to find all the indexes where x is present in the input array. Save all the indexes in an array (in increasing order).
Do this recursively. Indexing in the array starts from 0.
Input Format :
Line 1 : An Integer N i.e. size of array
Line 2 : N integers which are elements of the array, separated by spaces
Line 3 : Integer x
Output Format :
indexes where x is present in the array (separated by space)
Constraints :
1 <= N <= 10^3
Sample Input :
5
9 8 10 8 8
8
Sample Output :
1 3 4
CODE:
*/


int allIndexes(int input[], int size, int x, int output[]) {

    if (size == 0) { 
        return 0; 
    } 
  
    // Getting the recursive answer 
    int smallAns = allIndexes(input + 1, 
                                    size - 1, x, output); 
  
   
    if (input[0] == x) { 
        for (int i = smallAns - 1; i >= 0; i--) { 
            output[i + 1] = output[i] + 1; 
        } 

        output[0] = 0; 
        smallAns++; 
    } 
    else { 

        for (int i = smallAns - 1; i >= 0; i--) { 
            output[i] = output[i] + 1; 
        } 
    } 
    return smallAns; 

}