class Main {
public static void main(String[] args) {
String source = "I am Tom, I am from China";
String target = "Tom";
char[] sourceCharArray = source.toCharArray();
char[] targetCharArray = target.toCharArray();
boolean matched = false;
for (int i = 0; i <= sourceCharArray.length - targetCharArray.length; i ++) {
if (target.isEmpty()) matched = true;
if (matched) break;
for (int j = 0; j < targetCharArray.length; j ++) {
if (sourceCharArray[i + j] == targetCharArray[j]) {
if (j == targetCharArray.length - 1) matched = true;
} else break;
}
}
String result = "\"" + target + "\"";
if (matched) result += " 在 "; else result += " 不在 ";
result += "\"" + source + "\"" + " 中出现。";
System.out.println(result);
}
}