import streamlit as st

def main():
    st.title("Simple Calculator")

    st.write("Perform basic arithmetic operations.")

    # Input fields
    num1 = st.number_input("Enter the first number:", value=0.0)
    num2 = st.number_input("Enter the second number:", value=0.0)

    operation = st.selectbox("Select an operation:", ["Addition", "Subtraction", "Multiplication", "Division"])

    # Perform calculation
    if operation == "Addition":
        result = num1 + num2
        st.success(f"The result of {num1} + {num2} is {result}.")
    elif operation == "Subtraction":
        result = num1 - num2
        st.success(f"The result of {num1} - {num2} is {result}.")
    elif operation == "Multiplication":
        result = num1 * num2
        st.success(f"The result of {num1} * {num2} is {result}.")
    elif operation == "Division":
        if num2 != 0:
            result = num1 / num2
            st.success(f"The result of {num1} / {num2} is {result}.")
        else:
            st.error("Division by zero is not allowed.")

if __name__ == "__main__":
    main()