笨办法学Python ex03

数字和数学计算

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• 输入：

# -- coding: utf-8 --

print "I will now count my chickens:"
print "Roosters", 100 - 25* 3 % 4

print "Now I will count the eggs:"

print 3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6

print "Is it true that 3 + 2 < 5 - 7?"

print 3 + 2 < 5 - 7

print "What is 3 + 2?", 3 + 2
print "What is 5 - 7?", 5 - 7

print "Oh, that's why it's False."

print "How about some more."

print "Is it greater?", 5 > -2
print "Is it greater or equal?", 5 >= -2
print "Is it less or equla?", 5 <= -2

• 运行：

附加题

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• 浮点数(floating point number)

“浮点数”的定义是相对于“定点数”来说的。
在计算机内部，数据以二进制的形式存储和运算，而计算机内表示的数，又被分成整数和实数两大类。
其中整数一般用定点数表示，定点数指小数点在数中有固定的位置（一般来说整数的小数点都在最末位数后）。
实数一般用浮点数表示，因为它的小数点位置不固定。浮点数是既有整数又有小数的数，纯小数可以看作实数的特例。

• 使用浮点数重写一遍 ex3.py，让它的计算结果更准确(提示: 20.0 是一个浮点数)。

# -- coding: utf-8 --

print "I will now count my chickens:"
print "Roosters", 100.0- 25.0* 3.0 % 4.0

print "Now I will count the eggs:"

print 3.0 + 2.0 + 1.0 - 5.0 + 4.0 % 2.0 - 1.0 / 4.0 + 6.0

print "Is it true that 3.0 + 2.0 < 5.0 - 7.0?"

print 3.0 + 2.0 < 5.0 - 7.0

print "What is 3.0 + 2.0?", 3.0 + 2.0
print "What is 5.0 - 7.0?", 5.0 - 7.0

print "Oh, that's why it's False."

print "How about some more."

print "Is it greater?", 5.0 > -2.0
print "Is it greater or equal?", 5.0 >= -2.0
print "Is it less or equla?", 5.0 <= -2.0

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