python学习实例（2）

ゝ一纸荒年。 2022-05-08 14:03 151阅读 0赞

#===================================
    #2.2 不同进制间的转换
    #===================================
    
    
    #+++++++++++++++++++++++++++++++++++
    #2.2.1.	二进制数转换为十进制数
    #+++++++++++++++++++++++++++++++++++
    
    #<程序：2-to-10进制转换>
    b=input("Please enter a binary number:")
    d=0; 
    for i in range(0,len(b)):
        if b[i] == '1':
            weight = 2**(len(b)-i-1)
            d = d+weight;
    print(d)
    
    
    
    #<程序：改进后的2-to-10进制转换>
    b=input("Please enter a binary number:")
    d=0; weight=2**(len(b)-1);
    for i in range(0,len(b)):
        if b[i] == '1':
            d = d+weight;
        weight=weight//2;       #‘//’是整数除法
    print(d)
    
    
    
    
    #+++++++++++++++++++++++++++++++++++
    #2.2.2. 十进制数转换为二进制数
    #+++++++++++++++++++++++++++++++++++
    
    #<程序：整数的10-to-2进制转换>
    x= int(input("Please enter a decimal number:"))
    r = 0;
    Rs = [];
    while(x != 0):
        r = x% 2
        x = x//2
        Rs = [r]+Rs
    for i in range(0,len(Rs)):   
    #从最高位到最低位依次输出；Rs[0]存的是最高位， Rs[len(Rs)-1]存的是最低位。
        print(Rs[i],end='')
    
    
    
    #<程序：整数的10-to-2进制转换-递归>
    def convert(x):		 #把10进制数x转换为2进制数，并返回结果列表。
        if x<2: return([x])     #x=0 或 1，所以返回x
        r= x%2; 			#r 是2除x的余数
        return(convert(x//2)+[r])   # 结果=[x//2的二进制，r]
    
    num = int(input("Please enter a decimal number:"))
    Rs= convert(num)
    for i in range(0, len(Rs)):
        print (Rs[i],end='')
    
    
    #=====================================================================================
        
    
    
    #===================================
    #2.4. 一切都是逻辑（Logic）
    #===================================
    
    #+++++++++++++++++++++++++++++++++++
    #2.4.3. 用逻辑做加法
    #+++++++++++++++++++++++++++++++++++
    
    
    #<程序: 全加器>
    def FA(a,b,c):  # Full adder
         Carry = (a and b) or (b and c) or (a and c)
         Sum = (a and b and c) or (a and (not b) and (not c)) \
               or ((not a) and b and (not c)) or ((not a) and (not b) and c)
         return Carry, Sum
    
    
    
    #<程序：完整的加法器 Carry Ripple adder>
    def  add(x,y): # x, y are lists of True or False, c is True or False
                    # return carry and a list of x+y
        while len(x) < len(y): x = [False]+x    #前面补0
        while len(y) < len(x): y = [False]+y	#前面补0
        L=[];Carry=False
        for i in range(len(x)-1,-1,-1):  #从最后一位一个个往前加
            Carry,Sum=FA(x[i],y[i],Carry)
            L=L+[Sum]
        return (Carry, L)
    
    
    
    #<程序：乘法器>
    def multiplier(x,y):    # 求x*y
         S=[];
         for i in range(len(y)-1,-1,-1):
             if y[i] == True:     	#y[i]是 1，要将x加进到S
                 C, S=add(S,x)
                 if C==True: S=[C]+S
             x=x+[False]			#每一次x都要向左移一位，后面补0
         return(S)