import matplotlib.pyplot as plt
from matplotlib import cm
import math
import numpy as np

x_labels = [ 'C++', 'Ruby', 'Python', 'Php' ]
x_values = [ 20, 10, 30, 15 ]
x_explode = (0, 0, 0.1, 0) 

plt.pie(x_values, labels=x_labels, autopct='%1.1f%%', explode=x_explode)
plt.title("Utilisation des langages de programmation")
plt.savefig('img/plot_pie_chart.png')
plt.show()