C Language string proben

#include <stdio.h>
#include <string.h>
int main()
{
char s[1002], word[100];
int i, j, length, is_ word_started;
gets(s);
length= strlen(s);
is_ word_started= 0;
for(i= 0, j= 0; i<length; i++) {
    if(s[i] >= 'a' && s[i] <= 'z') {
        if(is_ word_started == 0) {
            is_ word_started= 1;
            word[j]= 'A' + s[i] - 'a';
            j++;
            }
           else {
           word[j]= s[i];
           j++;
        }
    }
    else if(s[i] >= 'A' && s[i] <= 'Z') {
        if(is_ word_started == 0) {
            is_ word_started= 1;
        }
        word[j]= s[i];
        j++;
    }
    else if(s[i] >= '0' && s[i] <= '9') {
        if(is_ word_started == 0) {
            is_ word_started= 1;
        }
        word[j]= s[i];
        j++;
    }
    else {
        if(is_ word_started == 1) {
            is_ word_started= 0;
            word[j]= '\0';
            printf("%s\n", word);
            j= 0;
        }
    }
}
return 0;
}