C :: How To Find Word And Insert Another Word After That In Text

I have text (string) and I want to find a given word (it's ok!) and then insert another given word after the first word. The original string is beeing copied into a new string. But something is going wrong!!! Where is my mistake?

(I have some patches...)

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//insert "new_word" after each occurence of "word"
int main(){
char A[100]="In the sentence words the and the.";

[Code]...