Word in a java string

I am very new to Java and as a starter I have been offered to try this at home.

Write a program that will find out number of occurences of a smaller string in a bigger string as a part of it as well as an individual word. For example,

Bigger string = "I AM IN AMSTERDAM", smaller string = "AM".

Output: As part of string: 3, as a part of word: 1.

While I did nail the second part (as a part of word), and even had my go at the first one (searching for the word as a part of the string), I just don't seem to figure out how to crack the first part. It keeps on displaying 1 for me with the example input, where it should be 3.

I have definitely made an error- I'll be really grateful if you could point out the error and rectify it. As a request, I am curious learner- so if possible (at your will)- please provide an explanation as to why so.

import java.util.Scanner;
public class Program {
static Scanner sc = new Scanner(System.in);
static String search,searchstring;
static int n;
void input(){
    System.out.println("What do you want to do?"); System.out.println("1.     
Search as part of string?");
    System.out.println("2. Search as part of word?");
    int n = sc.nextInt();
    System.out.println("Enter the main string"); searchstring = 
sc.nextLine();
    sc.nextLine(); //Clear buffer
    System.out.println("Enter the search string"); search = sc.nextLine();
}
static int asPartOfWord(String main,String search){
    int count = 0; 
    char c; String w = "";
    for (int i = 0; i<main.length();i++){
        c = main.charAt(i);
        if (!(c==' ')){
            w += c;
        }
        else {
            if (w.equals(search)){
                count++;
            }
            w = ""; // Flush old value of w
        }
    }
    return count;
}
static int asPartOfString(String main,String search){
    int count = 0;
    char c; String w = ""; //Stores the word 
    for (int i = 0; i<main.length();i++){
        c = main.charAt(i);
        if (!(c==' ')){
            w += c;
        }
        else {
            if (w.length()==search.length()){
                if (w.equals(search)){
                    count++;
                }
            }
            w = ""; // Replace with new value, no string
        }
    }
    return count;
}
public static void main(String[] args){
    Program a = new Program();
    a.input();
    switch(n){
        case 1: System.out.println("Total occurences: " + 
         asPartOfString(searchstring,search));
        case 2: System.out.println("Total occurences: " +  
         asPartOfWord(searchstring,search));
        default: System.out.println("ERROR: No valid number entered");
    }
  }
}

EDIT: I will be using the loop structure.

Solution

A simpler way would be to use regular expressions (that probably defeats the idea of writing it yourself, although learning regexes is a good idea because they are very powerful: as you can see the core of my code is 4 lines long in the countMatches method).

public static void main(String... args) {
  String bigger = "I AM IN AMSTERDAM";
  String smaller = "AM";

  System.out.println("Output: As part of string: " + countMatches(bigger, smaller) +
          ", as a part of word: " + countMatches(bigger, "\\b" + smaller + "\\b"));
}

private static int countMatches(String in, String regex) {
  Matcher m = Pattern.compile(regex).matcher(in);
  int count = 0;
  while (m.find()) count++;
  return count;
}

How does it work?

we create a Matcher that will find a specific pattern in your string, and then iterate to find the next match until there is none left and increment a counter
the patterns themselves: "AM" will find any occurrence of AM in the string, in any position. "\\bAM\\b" will only match whole words (\\b is a word delimiter).

That may not be what you were looking for but I thought it'd be interesting to see another approach. An technically, I am using a loop :-)