Reading input char by char using realloc in C

Question

I would like to read input char by char and save it as a word into char* array. I don't know how long the input will be, so i want to alloc the memmory dynamicaly. The program ends,when the char is whitespace. How can i do this using realloc? There is my code:

#include <stdio.h>
int main(void) {
    char *word=malloc(1*sizeof(char));
    char c;
    int numOfChars=0;
    c=getchar();
    word[0]=c;
    numOfChars++;
    while((c=getchar())!=' '){
        numOfChars++;
        realloc(word,numOfChars);
        word[numofChars-1]=c;
    }
    printf("%s", word);

    return 0;
}

Example input:Word Example output:Word

Answer 1

The program can look the following way. Take into account that the input is buffered and filled until a new line character is entered that is also a white space character. And the result word must be zero terminated if you are going to use format specifier %s to output it.

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

int main( void )
{
    int c;
    size_t n;
    char *word;
    char *tmp;

    n = 0;
    word = malloc( n + 1 );
    word[n++] = '\0';

    printf( "Enter a word: " );

    while ( ( c = getchar() ) != EOF && !isspace( c ) && ( tmp = realloc( word, n + 1 ) ) != NULL )
    {
        word = tmp;
        word[n-1] = c;
        word[n++] = '\0';
    }

    printf( "You've entered \"%s\"\n", word );

    free( word );
}        

The program output might look like

Enter a word: Hello
You've entered "Hello"