Find the nearest/closest value in a sorted List

Question

I was wondering if it is possible to find the closest element in a List for a element that is not there.

For example if we had the valu

Answer 1

There are two methods to achieve the result-

1. lower_bound
2. binary search

I prefer to use the lower_bound method, it's short :)

int pos=lower_bound(v.begin(),v.end(),value);
if(pos!=0&&target!=v[pos])
    if(abs(v[pos]-value)>abs(value-v[pos-1]))
        pos=pos-1;

For binary search, you can refer to the above answers, as my code will seem like a copy paste of their code. Note that I have declared the array globally here.

binarysearch(int low,int high,int val)
{
    if(val<=arr[0])
        return 0;
    if(val>=arr[n-1])
        return arr[n-1];
    while(low<=high)
    {
        int mid=(low+high)/2;
        if(v[mid]>val)
            return binarysearch(low,mid-1,val);
        else if(v[mid]=abs(val-v[high]))
        return high;
    else 
        return low;
}