print("=== Strings Demo ===");
print("");

print("--- String Literals ---");
single = 'Single quotes';
double = "Double quotes";
print(single);
print(double);

print("");
print("--- String Concatenation ---");
first = "Hello";
second = "World";
combined = first + " " + second;
print("Concatenated:", combined);

greeting = "Hi";
greeting += " there!";
print("Using +=:", greeting);

print("");
print("--- String Length ---");
text = "Hello, World!";
print("Text:", text);
print("Length:", text.length);

print("");
print("--- Substring (substr) ---");
myStr = "Hello, World!";
print("Original:", myStr);
print("substr(0, 5):", myStr.substr(0, 5));
print("substr(7, 5):", myStr.substr(7, 5));

print("");
print("--- String Split ---");
csv = "apple,banana,cherry";
parts = csv.split(",");
print("CSV:", csv);
print("Split result:");
for (i = 0; i < len(parts); i++) {
    print("  ", parts[i]);
}

print("");
print("--- String Count ---");
text = "abracadabra";
print("Text:", text);
print("Count of 'a':", text.count("a"));
print("Count of 'br':", text.count("br"));

print("");
print("--- String indexOf ---");
testStr = "Hello, World!";
print("String:", testStr);
print("indexOf('World'):", testStr.indexOf("World"));
print("indexOf('o'):", testStr.indexOf("o"));

print("");
print("--- Case Conversion ---");
mixed = "Hello World";
print("Original:", mixed);
print("toUpper():", mixed.toUpper());
print("toLower():", mixed.toLower());

print("");
print("--- String Trim ---");
padded = "   spaces   ";
print("Before trim:", padded);
print("After trim:", padded.trim());

print("");
print("--- String Replace ---");
original = "Hello World";
replaced = original.replace("World", "Nano");
print("Replace 'World' with 'Nano':", replaced);

print("");
print("--- Type Conversion ---");
num = 42;
numStr = str(num);
print("Number to string:", numStr);

strNum = "123";
parsed = int(strNum);
print("String to number:", parsed);

print("");
print("All string tests completed");