Тип массива "char [200]" является неназначаемым - C (СИ)

#include STDIO.H
#define num 1000 
int 
main () 
{ 
char c; 
int i = 0; 
int j; 
char str[num] = {0}; 
int count = 0; 
printf ("Input string: "); 
while ((c = getchar ()) != '\n') 
{ 
str[i] = c; 
i++; 
} 
for(i = 0; i < num; i++) 
{ 
if((str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z')) 
{ 
count++; 
} 
else 
{ 
if ((str[i - 1] >= 'a' && str[i - 1] <= 'z') || (str[i - 1] >= 'A' && str[i - 1] <= 'Z')) 
{ 
for(j = i - 1; (j >= 0) && (str[j] >= 'a' && str[j] <= 'z') || (str[j] >= 'A' && str[j] <= 'Z') && (j < count); j--) 
{ 
printf("%c", str[j]); 
} 
printf ("\n"); 
} 
count = 0; 
} 
} 
return 0; 
}

#include STDIO.H
#define NUM 1000 
 
char*
words_in_reverse(char *str)
{
    int i = 0;
    int j;
    int k = 0;
    int count = 0;
    char output[NUM];
    for (i = 0; i < NUM; i++)
    {
        if ((str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z'))
        {
            count++;
        }
        else
        {
            if ((str[i - 1] >= 'a' && str[i - 1] <= 'z') || (str[i - 1] >= 'A' && str[i - 1] <= 'Z'))
            {
                for (j = i - 1; (j >= 0) && (str[j] >= 'a' && str[j] <= 'z') || (str[j] >= 'A' && str[j] <= 'Z') && (j < count); j--)
                {
                    printf("%c", str[j]);
                    output[k] = str[j];
                    k++;
                }
                output[k] = '\n';
                k++;
            }
            count = 0;
        }
    }
    return output;
}
 
int
main()
{
    char c;
    int i;
    int j;
    char str[NUM] = { 0 };
    char newstr[NUM];
    printf("Input string: ");
    while ((c = getchar()) != '\n')
    {
        str[i] = c;
        i++;
    }
    newstr = words_in_reverse(str);
    for (j = 0; j < NUM; j++)
    {
        printf("%c", newstr[j]);
    }
    return 0;
}