Create app.py

app.py

@@ -0,0 +1,159 @@
+import streamlit as st
+import math
+import pandas as pd
+
+st.set_page_config(page_title="Mobile Calculator", page_icon="🧮", layout="centered")
+
+# ---------------- SESSION ----------------
+if "expression" not in st.session_state:
+    st.session_state.expression = ""
+
+if "history" not in st.session_state:
+    st.session_state.history = []
+
+# ---------------- SAFE EVAL ----------------
+def safe_eval(expr):
+    allowed = {
+        "sqrt": math.sqrt,
+        "sin": math.sin,
+        "cos": math.cos,
+        "tan": math.tan,
+        "log": math.log10,
+        "pi": math.pi,
+        "e": math.e
+    }
+    try:
+        return eval(expr, {"__builtins__": None}, allowed)
+    except:
+        return "Error"
+
+# ---------------- STYLE ----------------
+st.markdown("""
+<style>
+body {background-color:#0f172a;}
+.display {
+    background:#1e293b;
+    color:white;
+    padding:20px;
+    border-radius:20px;
+    font-size:32px;
+    text-align:right;
+    margin-bottom:10px;
+}
+.stButton>button {
+    height:65px;
+    border-radius:20px;
+    font-size:22px;
+    font-weight:bold;
+}
+</style>
+""", unsafe_allow_html=True)
+
+st.title("🧮 Advanced Mobile Calculator")
+
+# ---------------- DISPLAY ----------------
+st.markdown(f"<div class='display'>{st.session_state.expression or 0}</div>", unsafe_allow_html=True)
+
+if st.session_state.expression:
+    st.write("Result:", safe_eval(st.session_state.expression))
+
+# ---------------- BUTTON FUNCTIONS ----------------
+def add(val):
+    st.session_state.expression += str(val)
+
+def clear():
+    st.session_state.expression = ""
+
+def delete():
+    st.session_state.expression = st.session_state.expression[:-1]
+
+def calculate():
+    result = safe_eval(st.session_state.expression)
+    st.session_state.history.append(f"{st.session_state.expression} = {result}")
+    st.session_state.expression = str(result)
+
+# ---------------- MOBILE GRID ----------------
+
+layout = [
+    ["C", "DEL", "(", ")"],
+    ["7", "8", "9", "/"],
+    ["4", "5", "6", "*"],
+    ["1", "2", "3", "-"],
+    ["0", ".", "+", "="],
+]
+
+for row in layout:
+    cols = st.columns(4)
+    for i, button in enumerate(row):
+        if button == "C":
+            cols[i].button(button, on_click=clear)
+        elif button == "DEL":
+            cols[i].button(button, on_click=delete)
+        elif button == "=":
+            cols[i].button(button, on_click=calculate)
+        else:
+            cols[i].button(button, on_click=add, args=(button,))
+
+st.markdown("---")
+
+# ---------------- SCIENTIFIC SECTION ----------------
+st.subheader("Scientific Functions")
+
+sci_cols = st.columns(4)
+sci_cols[0].button("sqrt(", on_click=add, args=("sqrt(",))
+sci_cols[1].button("sin(", on_click=add, args=("sin(",))
+sci_cols[2].button("cos(", on_click=add, args=("cos(",))
+sci_cols[3].button("log(", on_click=add, args=("log(",))
+
+st.markdown("---")
+
+# ---------------- GRAPH PLOT ----------------
+st.subheader("📊 Plot Function")
+
+plot_expr = st.text_input("Enter function in x (example: sin(x), x**2)")
+
+if st.button("Plot"):
+    try:
+        x_vals = [i/10 for i in range(-100, 100)]
+        y_vals = []
+
+        for x in x_vals:
+            y = eval(
+                plot_expr,
+                {"__builtins__": None},
+                {
+                    "x": x,
+                    "sin": math.sin,
+                    "cos": math.cos,
+                    "tan": math.tan,
+                    "sqrt": math.sqrt,
+                    "log": math.log10,
+                    "pi": math.pi,
+                    "e": math.e
+                }
+            )
+            y_vals.append(y)
+
+        df = pd.DataFrame({"x": x_vals, "y": y_vals})
+        st.line_chart(df.set_index("x"))
+
+    except:
+        st.error("Invalid Function")
+
+st.markdown("---")
+
+# ---------------- HISTORY ----------------
+st.subheader("📜 History")
+
+if st.session_state.history:
+    for item in reversed(st.session_state.history):
+        st.write(item)
+
+    df = pd.DataFrame(st.session_state.history, columns=["Calculations"])
+    st.download_button(
+        "Download History",
+        df.to_csv(index=False),
+        file_name="history.csv"
+    )
+else:
+    st.info("No calculations yet.")