finished project

app/index.tsx

@@ -0,0 +1,95 @@
+import React, { useState } from 'react';
+import { View, Text, TextInput, Button, StyleSheet } from 'react-native';
+
+const BMICalculator = () => {
+  const [weight, setWeight] = useState<string>('');
+  const [height, setHeight] = useState<string>('');
+  const [bmi, setBmi] = useState<string | null>(null);
+  const [status, setStatus] = useState<string>('');
+
+  const calculateBMI = () => {
+    const w = parseFloat(weight);
+    const h = parseFloat(height) / 100;
+    if (w > 0 && h > 0) {
+      const bmiValue = (w / (h * h)).toFixed(2);
+      setBmi(bmiValue);
+      setStatus(getBMIStatus(bmiValue));
+    } else {
+      setBmi(null);
+      setStatus('');
+    }
+  };
+
+  const getBMIStatus = (bmi: string): string => {
+    const bmiValue = parseFloat(bmi);
+    if (bmiValue < 18.5) return 'Alulsúlyos';
+    if (bmiValue < 24.9) return 'Normál súlyú';
+    if (bmiValue < 29.9) return 'Túlsúlyos';
+    return 'Elhízott';
+  };
+
+  return (
+    <View style={styles.container}>
+      <Text style={styles.title}>BMI Kalkulátor</Text>
+      <TextInput
+        style={styles.input}
+        placeholder="Súly (kg)"
+        keyboardType="numeric"
+        value={weight}
+        onChangeText={setWeight}
+      />
+      <TextInput
+        style={styles.input}
+        placeholder="Magasság (cm)"
+        keyboardType="numeric"
+        value={height}
+        onChangeText={setHeight}
+      />
+      <Button title="BMI számítása" onPress={calculateBMI} />
+      {bmi && (
+        <View style={styles.resultContainer}>
+          <Text style={styles.result}>BMI: {bmi}</Text>
+          <Text style={styles.status}>{status}</Text>
+        </View>
+      )}
+    </View>
+  );
+};
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    justifyContent: 'center',
+    alignItems: 'center',
+    padding: 20,
+    backgroundColor: '#f5f5f5',
+  },
+  title: {
+    fontSize: 24,
+    fontWeight: 'bold',
+    marginBottom: 20,
+  },
+  input: {
+    width: '80%',
+    padding: 10,
+    borderWidth: 1,
+    borderColor: '#ccc',
+    borderRadius: 5,
+    marginBottom: 10,
+    backgroundColor: '#fff',
+  },
+  resultContainer: {
+    marginTop: 20,
+    alignItems: 'center',
+  },
+  result: {
+    fontSize: 20,
+    fontWeight: 'bold',
+  },
+  status: {
+    fontSize: 18,
+    color: 'blue',
+  },
+});
+
+export default BMICalculator;