words_counter.c

#include <stdio.h>
#include <string.h>
int main(){
    char str[40];
    int i, word = 1;
    printf("Enter a sentence:\n");
    scanf("%[^\n]s", str);
    for( i = 0 ; str[i] != '\0' ; ++i){
        if(str[i] == ' ')
            word++;
    }
    printf("Number of words = %d", word);
}