#include <stdio.h>
    #include <math.h>
    #define N 100000
    int main(){
        double n;
        double line[N];
        int i = 0 ;

        while(scanf("%lf",&n) != EOF)
        {
            line[i++] = n;
        }
        while(i-- > 1)
        {
            printf("%0.4lf\n",sqrt(line[i]));
        }
        printf("%0.4lf",sqrt(line[i]));
        return 0;
    }

> #define N 100000

Why do you think 100,000 is enough?
Why do you place so big arrays on stack? You should better use std::vector or dynamic allocation.
Why do you have 2 equal "printf" lines? You should better change "while" condition.