求给定整数的所有素因子
1. 题目：求给定整数的所有素因子
2. 要求：输入一个整数，求出其所有素因子，并表现为乘积方式，求因子的算法用子程序来实现。例如，输入480,输出480=2*2*2*2*2*3*5
C++代码如下
1 //The program is to find all the prime factors of a number
2 //Author:Karllen
3 //Date: 05/22/2014
4 #include <iostream>
5
6 void findPfactor(int n); // Find the factor belongs to prime
7 int main(void)
8 {
9 int n;
10 std::cin>>n;
11 findPfactor(n);
12 system("pause");
13 return 0;
14 }
15
16 void findPfactor(int n)
17 {
18 int i = 2;
19 while (i<n)
20 {
21 while (n%i==0) //The i is a factor of n
22 {
23 n = n/i;
24 std::cout<<i;
25 std::cout<<‘*‘;
26 }
27 ++i;
28 }
29 std::cout<<n<<std::endl;
30 }
汇编代码如下：
1 ; Example assembly language program
2 ; Author: Karllen
3 ; Date: revised 05/2014
4
5 .386
6 .MODEL FLAT
7
8 ExitProcess PROTO NEAR32 stdcall, dwExitCode:DWORD
9
10 INCLUDE io.h ; header file for input/output
11
12 cr EQU 0dh ; carriage return character
13 Lf EQU 0ah ; line feed
14
15 .STACK 4096 ; reserve 4096-byte stack
16
17 .DATA ; reserve storage for data
18 flai DWORD ?
19 temp DWORD ?
20 crlf BYTE "*",0
21 eqll BYTE "=",0
22 prompt BYTE "Enter a number to find all the prime factors",cr,Lf,0
23 fl DWORD ?
24 value BYTE 11 DUP(?),0
25 char BYTE 1 DUP(?)
26
27 PUBLIC _start
28 .CODE ; start of main program code
29 _start:
30 output prompt
31 input value,11
32 atod value
33 push eax
34 call byteInput
35 add esp,4
36
37 output eqll
38
39 push eax
40 call findPfactor
41 add esp,4
42
43 INVOKE ExitProcess, 0 ; exit with return code 0
44
45
46 findPfactor PROC NEAR32 ;find the prime of factor
47 push ebp
48 mov ebp,esp
49
50 mov eax,[ebp+8]
51 mov flai,eax
52 mov ecx,2
53 mov ebx,ecx
54 doFind:
55 mov ecx,ebx
56 cmp ecx,flai
57 je endFind
58 doFactor:
59 mov temp,eax
60 cdq
61 idiv ecx
62 ;eax = eax/ecx
63 cmp edx,0
64 jne endFactor
65 ;dtoa value,ecx
66 ;output value
67 push ecx
68 call byteInput
69 add esp,4
70 output crlf
71
72 jmp doFactor
73 endFactor:
74 mov eax,temp
75 inc ebx
76 jmp doFind
77 endFind:
78 pop ebp
79 ret
80
81 findPfactor ENDP
82
83 byteInput PROC NEAR32
84 push ebp
85 mov ebp,esp
86
87 push ebx
88 push eax
89 push edx
90
91 mov fl,0
92 mov ebx,10
93 mov eax,[ebp+8]
94 doWh:
95 cdq
96 idiv ebx
97 push edx
98 inc fl
99 cmp eax,0
100 je enddoWh
101
102
103 jmp doWh
104 enddoWh:
105
106 doPrint:
107
108 cmp fl,0
109 je enddoPrint
110 dec fl
111 pop edx
112 mov char,dl
113 add char,‘0‘
114 output char
115 jmp doPrint
116 enddoPrint:
117 pop edx
118 pop eax
119 pop ebx
120 pop ebp
121 ret
122
123 byteInput ENDP
124
125 END ; end of source code
测试结果：
时间： 2024-11-10 08:06:29