Pattern Matching Program in C Language

Given a text txt[0..n-1] and a pattern pat[0..m-1], write a function search(char pat[], char txt[]) that prints all occurrences of pat[] in txt[]. Assume that n > m.

Examples:

1) Input:

txt[] = "THIS IS A TEST TEXT"
pat[] = "TEST"

Output:

Pattern found at index 10

2) Input:

txt[] = "AABAACAADAABAAABAA"
pat[] = "AABA"

Output:

Pattern found at index 0
Pattern found at index 9
Pattern found at index 13

I want the full program in C language