Python 模拟竖式大数乘法，python竖式大数乘法,python内置了大数运

Python 模拟竖式大数乘法，python竖式大数乘法,python内置了大数运

python内置了大数运算,非常方便,无聊写了个模拟竖式乘法的小程序,可以计算任意位数乘法.python爱好者,欢迎交流

运行结果及时间

                   123456709*        1234567890987654321----------------------------                   123456709                  246913418                  370370127                  493826836                  617283545                  740740254                  864196963                  987653672                 1111110381                  000000000                 1111110381                  987653672                  864196963                  740740254                  617283545                  493826836                  370370127                  246913418                  123456709                  ----------------------------152415688858406562100289589Elapsed time: 0.10666831 seconds         1234567890987654321*                  123456709----------------------------        11111111018888888889        0000000000000000000        8641975236913580247        7407407345925925926        6172839454938271605        4938271563950617284        3703703672962962963        2469135781975308642        1234567890987654321        ----------------------------152415688858406562100289589Elapsed time: 0.05573613 seconds

[Python]代码

#! /urs/bin/env pythonfrom mytictoc import tic, toc# big intiger multiplicationdef bigmul(a,b):    sa = str(a)    sb = str(b)    resultline = ' '*(len(sa)+len(sb))    #   a    # * b    print    print resultline[:-len(sa)]+sa    print '*'+resultline[:-len(sb)-1]+sb    # ---    print '-'*(len(sa)+len(sb))    #   ###    #  ###    # ###    result_list = []    cursp = 0    for db in sb[::-1]:        if int(db)==0:            result = '0'*len(sa)        else:            result = ''            carrier = 0            for da in sa[::-1]:                #print db,da                mr = int(db)*int(da)+carrier                carrier = mr/10                result += str(mr%10)            if carrier!=0:                result += str(carrier)        result = result[::-1]+' '*cursp        cursp += 1        result_list.append(resultline[:-len(result)]+result)        print result_list[-1]    # ----    print '-'*(len(sa)+len(sb))    # result    print str(sum([int(x.replace(' ','0')) for x in result_list])) # unit testdef main():    a = 1234567890987654321    b = 123456709    tic()    bigmul(b,a)    toc()    tic()    bigmul(a,b)    toc()if __name__=='__main__':    main()