Why does the code in c not end and forces me to press crl+z to end the execution?

I´ve made a simple code to print in reverse the numbers written between letters.
For example: if I write on the terminal:
1 2 3 hello 4 5 6 end
or enter that in the function through a txt its returning the expected values:
3 2 1\n
6 5 4\n
but it doesn´t end, Im forced to press crl+z to be able to use the trminal again.

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

#define MAX_NUM 64

int main() {
    int num[MAX_NUM];
    int size = 0, i;
    char word[20];
    while (scanf("%d", &num[size]) != 0) {
        size++;
        while(scanf("%d", &num[size]) != 0){
            size++;
        }
        if (scanf("%s",word) != 0 || size == MAX_NUM) {
            for (i = size - 1; i >= 0; i--) {
                if(i == 0)
                    printf("%d", num[i]);
                else
                    printf("%d ", num[i]);
            }
            printf("\n");
            size = 0;
        }
    }
    return 0;
}

>Solution :

Why does the code in c not end and forces me to press crl+z to end the execution?

Because scanf cannot read your mind. For instance, when you call scanf("%d", &num[size]) and there is not presently any more data available to read, scanf doesn’t know that you don’t intend ever to present any more. Before it returns, it needs to see an end-of-input or error signal or a character that it cannot match to the format. In Windows, Ctrl-Z signals end-of-input on the standard input of a program running in the terminal.