[The assignment](https://i.stack.imgur.com/33L74.jpg)

Below is what I have so far. It's not much and it's probably incorrect so any help is appreciated. 

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

int main()
{
    char word[1000]; 
    char output[1000];
    int n = 50;
    int i, j;

    printf("Please enter a sentence no larger than 1000 characters: ");
    for(i = 0, i < n, i++)
        scanf("%s", &word[i]);

    int length = strlen(word);
    for(i = 0, i < length, i++) {
        if (length <= 4)
        else
        if(word[i] >= 'A' && word[i] <= 'Z') {
            output[i] = word[i];
        }  
    }
    return 0;
}

```