Locate a word in String - STRSTR

/* Locate a word in String - STRSTR */

#include<stdio.h>

int main()
{
 char str1[100], str2[100];
 int i,j,k;
 printf("Please enter first string: ");
 // gets(str1); 
 // fgets is a better option over gets to read multiword string .
 fgets(str1, 100, stdin);
 // Following can be added for extra precaution for '\n' character
 // if(str1[length(str1)-1] == '\n') str1[strlen(str1)-1]=NULL;

 printf("Please enter a word: ");
 // gets(str2); 
 fgets(str2, 100, stdin);
 // if(str2[length(str2)-1] == '\n') str2[strlen(str2)-1]=NULL;
 
 for(i=0;str1[i]!=NULL;i++)
 {
  for(k=i,j=0;str2[j]!=NULL;j++,k++)
   if(str1[k]!=str2[j])
    break;
  if(str2[j]==NULL)
  {
   printf("\"%s\" is the sub string of \"%s\" at %d location",str2,str1,k+1);
   i=-1;
   break;
  }
 }
 if(i!=-1)
  printf("\"%s\" is not the sub string of \"%s\"",str2,str1);

 return 0;
}