# Mod1.py
import math

def calc_function(a, x):
    if x == 0:
        return a
    return a * math.sin(x) / x

def calculate_interval(a, x_start=0.5, x_end=50, step=0.5):
    results = []
    x = x_start
    while x <= x_end:
        value = calc_function(a, x)
        results.append((x, value))
        x += step
    return results

def write_to_file(results, filename="output.txt"):
    with open(filename, 'w', encoding='utf-8') as f:
        for x, val in results:
            f.write(f"{val}\n")
    print(f"Данные записаны в файл: {filename}")

def plot_function(results):
    import matplotlib.pyplot as plt
    
    x_vals = [item[0] for item in results]
    y_vals = [item[1] for item in results]
    
    plt.figure(figsize=(10, 5))
    plt.plot(x_vals, y_vals, label="f(x) = a * sin(x) / x", color='blue')
    plt.title("График функции f(x) = a * sin(x) / x")
    plt.xlabel("x")
    plt.ylabel("f(x)")
    plt.grid(True)
    plt.legend()
    plt.show()
