app.py

import streamlit as st

# Function to perform arithmetic operations
def calculate(num1, num2, operation):
    if operation == 'Add':
        return num1 + num2
    elif operation == 'Subtract':
        return num1 - num2
    elif operation == 'Multiply':
        return num1 * num2
    elif operation == 'Divide':
        if num2 == 0:
            return "Cannot divide by zero!"
        return num1 / num2
    else:
        return "Invalid operation"

# Streamlit UI - Customizing the interface for better user experience

# Title with custom styling
st.markdown("""
    <h1 style="text-align: center; color: #4CAF50;">Simple Calculator</h1>
    <p style="text-align: center; font-size: 18px;">Perform basic arithmetic operations: Add, Subtract, Multiply, Divide.</p>
    """, unsafe_allow_html=True)

# Create a layout with columns for inputs and result
col1, col2 = st.columns(2)

with col1:
    # User input for the first number
    num1 = st.number_input("Enter the first number", value=0.0, format="%.2f", step=0.1, key="num1")
    
with col2:
    # User input for the second number
    num2 = st.number_input("Enter the second number", value=0.0, format="%.2f", step=0.1, key="num2")

# Selectbox for the operation
operation = st.selectbox(
    "Select the operation",
    ("Add", "Subtract", "Multiply", "Divide"),
    key="operation"
)

# Add a button to calculate
if st.button("Calculate"):
    result = calculate(num1, num2, operation)
    st.markdown(f"### **Result: {result}**", unsafe_allow_html=True)

# Additional styling
st.markdown("""
    <style>
    .css-1v0mbdj {padding: 0.5rem 2rem;}
    .css-1cpxqw2 {background-color: #4CAF50; color: white;}
    .stButton button {border-radius: 5px;}
    </style>
    """, unsafe_allow_html=True)