算法题--rand5产生rand7

 1 #include <iostream>
 2 #include <string>
 3 #include <memory.h>
 4 #include <vector>
 5 #include <sstream>
 6 #include <math.h>
 7 #include <climits>
 8 #include <algorithm>
 9 #include <cstdlib>
10 using namespace std;
11 
12 int generate_5()
13 {
14     return 1+rand()%5;
15 }
16 
17 int generate_7()
18 {
19     int tmp = 30;
20     while(tmp > 26)
21     {
22         tmp = (5*generate_5()+generate_5());
23     }
24     return (tmp-3)/3;
25 }
26 
27 int main()
28 {
29     int cnt = 0;
30     while(cnt < 70)
31     {
32         cout<<generate_7()<<endl;
33         ++cnt;
34     }
35     return 0;
36 }