All indices of a number using recurrion

I am solving a problem in recursion to print all the indices of a number. For example: arr[] = {8,8,10,8,8} and element = 8 then we should have output array as: {0,1,3,4}

I am not getting the output as expected. Here is my code solution:

#include<iostream>
using namespace std;
int allIndexes(int input[], int size, int x, int output[]) {
    if(size==0){
        return 0;
    }
    if(input[0] == x){
        output[0] = 0;    
    }
    int ans = allIndexes(input+1,size-1,x,output);
    for(int i=1;i<ans;i++){
        output[i] = output[i]+1;
    }
    ans = ans+1;
    return ans;
}
int main(){
    int arr[] = {8,8,10,8,8},output[5]={0};
    int size = allIndexes(arr,5,8,output);
    cout<<size<<endl;
    for(int i=0;i<size-1;i++){
        cout<<output[i]<<" ";
    }
    return 0;
}

Why I am getting wrong?