$ cat area.ini

[numbers]
pi: 3.1415926535893971

[messages]
greeting: Welcome to the area calutation program!
question: plse enter the radius
result_message: The area is

from configparser import ConfigParser
CONFIGFILE = "area.ini"

config = ConfigParser()
#读取配置文件
config.read(CONFIGFILE)

print(config['messages'].get('greeting'))

radius = float(input(config['messages'].get('question') + ' '))

# 以空格结束以便接着在当前行打印：
print(config['messages'].get('result_message'),end=' ')
print(config['numbers'].getfloat('pi') * radius**2)