int rand7(){int s=0,c=7;while(c-->0)s+=rand5();return s%7+1;}

class Rand {

    public static void main(String[] args) {
        int[] nums = new int[7];
        // get a lot of numbers
        for(int i = 0; i < 10000000; i++) nums[rand7()-1]++;
        // print the results
        for(int i = 0; i < 7; i++) System.out.println((i+1) + ": " + nums[i]);
    }

    // just for rand5()
    static java.util.Random r = new java.util.Random();

    static int rand5() {
        return r.nextInt(5)+1; // Random.nextInt(n) returns 0..n-1, so add 1
    }

    static int rand7(){int s=0,c=7;while(c-->0)s+=rand5();return s%7+1;}

}

C:Documents and SettingsglowcoderMy Documents>java Rand
1: 1429828
2: 1429347
3: 1428328
4: 1426486
5: 1426784
6: 1429853
7: 1429374

C:Documents and SettingsglowcoderMy Documents>

function Rand7(){for(i=r=0;i<7;i++)r+=Rand5()%2;return r}

function Rand7(){for(i=r=0;i<7;i++)r+=Rand5()%2;return r}

sub rand7{($x=5*&rand5+&rand5-3)<24?int($x/3):&rand7}

sub rand7{($x=5*&rand5+&rand5)<30?$x%7+1:&rand7}

def rand7;x=8;while x>7 do x=rand5+5*rand5-5 end;x;end

def rand7;x=rand5+5*rand5-5;x>7 ?rand7: x;end

def Rand7():
  while True:
    x = (Rand5() - 1) * 5 + (Rand5() - 1)
    if x < 21: return x/3 + 1

(defun rand7()(let((n(-(+(rand5)(* 5(rand5)))5)))(if(> n 7)(rand7)n)))

int rand7(){int x=8;while(x>7)x=rand5()+5*rand5()-5;return x;}

function Rand7(){$x=8;while($x>7)$x=rand5()+5*rand5()-5;return $x;}

def rand7:Int={val r=5*(rand5-1)+rand5
if(r<8)r else rand7}

 1 2 3 4 5
1 1 2 3 4 5
2 6 7 8 ..
3 11 ..
4 ..
5

def rand7=(1 to 7).map(_=>rand5).sum%7+1

def rand7=((0/:(1 to 7))((a,_)=>a+rand5-1))%7+1

val rnd = util.Random
def rand5 = rnd.nextInt (5) + 1

int rand7(){int x=rand5()*5+rand5()-6;return x>21?rand7():x/3+1;}

int rand7(){int x=rand5()+5*rand5()-5;return x>7?rand7():x;}

function Rand7(){x=8;while(x>7)x=rand5()+5*rand5()-5;return x}

rand7 = lambda: sum(rand5() for i in range(7)) % 7 + 1

counter = [0] * 7
for i in range(100000):
     counter[rand7()] += 1

rand7=lambda:eval("+rand5()"*7)%7+1

unsigned int Rand4()
{
    unsigned int r = Rand5();

    while(r == 5)
        r = Rand5();

    return(r);
}

unsigned int myRand2()
{
    return((Rand4() - 1) & 1);
}

unsigned int Rand7()
{
    return(((myRand2() << 2) | (myRand2() << 1) | myRand2()) + 1);
}

int Rand7(){int n=0;for(int i=0;i<3;++i){int r=Rand5();while(r==5) r=Rand5();--r;r&=1;n|=r<<i;} return n;}

# Construct a Rand5 function
Rand5 <- function() sample(seq(5),1)
# And the golf
Rand7=function(r=Rand5())sample(1:(r/r+6),1)
# Or (same character count)
Rand7=function(r=Rand5())sample.int(r/r+6,1)
# Or even shorter(thanks to @Spacedman)
Rand7=function()sample(7)[Rand5()]

> test <- replicate(10^6,Rand7())
> table(test)
test
     1      2      3      4      5      6      7
142987 142547 143133 142719 142897 142869 142848

library(ggplot2)
qplot(test)

(defn rand7[](#(if(<% 8)%(rand7))(+(rand5)(*(rand5)5)-5)))

function Rand7(){for(x=0,i=1;i<8;x^=i*((k=Rand5())%2),i*=1+(k<5));return x?x:Rand7()}

int Rand7()
{
    int r = Rand5();
    int n = 5;
    do {
        r = (r - 1) * 5 + Rand5();
        int m = n * 5 / 7 * 7;
        if (r <= m) {
            return r % 7 + 1;
        }
        r -= m;
        n = n * 5 - m;
    } while (1);
}

142935 142751 142652 143299 142969 142691 142703

1 2      3      4     5    6   7 8  9 10
0 840180 112222 44433 2212 886 0 60 6 1

def rand7():
 while True:
  n=5*(rand5()-1)+(rand5()-1)
  if n<21:return n%7+1

int rand7(){int r;do{r=rand5()+5*rand5()-5;}while(r>7);return r;}

int result = 0;

for (int i = 0; i++; i<7)
    if (((rand(5) + rand(5)) % 2) //check if odd
        result += 1;

return result + 1;

rand7=function(n)sample(7,n,T)

> rand7(20)
 [1] 4 3 6 1 2 4 3 2 3 2 5 1 4 6 4 2 4 6 6 1
> rand7(20)
 [1] 1 2 5 2 6 4 6 1 7 1 1 3 7 6 4 7 4 2 1 2
> rand7(20)
 [1] 6 7 1 3 3 1 5 4 3 4 2 1 5 4 4 4 7 7 1 5

sub rand7{1while($_=5*&rand5-rand5)>6;$_+1}

sub rand7{1while($_=5*&rand5-rand5)>20;$_%7+1}

rand7={if(b==null)b=rand5();(b=(rand5()+b)%7+1)}

[1:5030, 2:4909, 3:5017, 4:4942, 5:5118, 6:4956, 7:5028]

Rand7=Rand5[]~Sum~{7}~Mod~7+1&

00000000  2f 72 61 6e 64 37 7b 38  7b 92 38 37 92 61 7b 92  |/rand7{8{.87.a{.|
00000010  40 7d 69 66 92 75 32 7b  72 61 6e 64 35 7d 92 83  |@}if.u2{rand5}..|
00000020  35 92 6c 92 01 35 92 a9  7d 92 65 7d 92 33        |5.l..5..}.e}.3|
0000002e

% This is the actual rand7 procedure.
/rand7{
  8{                      % potentialResult
    % only if the random number is less than or equal to 7, we're done
    dup 7 le{             % result
      exit                % result
    }if                   % potentialResult
    pop                   % -/-
    2{rand5}repeat        % randomNumber1 randomNumber2
    5 mul add 5 sub       % randomNumber1 + 5*randomNumber2 - 5 = potentialResult
  }loop
}def

%Now, some testing code.

% For testing, we use the built-in rand operator;
% Doesn't really give a 100% even distribution as it returns numbers
% from 0 to 2^31-1, which is of course not divisible by 5.
/rand5 {
  rand 5 mod 1 add
}def

% For testing, we initialize a dict that counts the number of times any number
% has been returned. Of course, we start the count at 0 for every number.
<<1 1 7{0}for>>begin

% Now we're calling the function quite a number of times
% and increment the counters accordingly.
1000000 {
  rand7 dup load 1 add def
}repeat

% Print the results
currentdict{
  2 array astore ==
}forall

int Rand7()
{
    return Rand5()+ Rand5()/2;
}

static unsigned int gi = 0;

int rand7()
{
    return (((rand() % 5 + 1) + (gi++ % 7)) % 7) + 1;
}

//call this seed before rand7
//maybe it's not best seed, if yo have any good idea tell me please
//and thanks JiminP again, he remind me to do this
void srand7()
{
    int i, n = time(0);
    for (i = 0; i < n % 7; i++)
        rand7();
}

1st get one number from 1 2 3 4 5 by rand5
2nd get one number from 2 3 4 5 6
3rd get one number from 3 4 5 6 7
4th get one number from 4 5 6 7 1
5th get one number from 5 6 7 1 2
5th get one number from 6 7 1 2 3
7th get one number from 7 1 2 3 4

8th get one number from 1 2 3 4 5
9th get one number from 2 3 4 5 6
......

(((rand() % 5 + 1) + (gi++ % 7)) % 7) + 1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

static unsigned int gi = 0;

//a = rand() % 5 + 1 is rand5 in C language,
//b = gi++ % 7 generates all permutations,
//c = (a + b) % 7 + 1, generates 1 - 7 uniformly.
//Dont forget call srand7 before rand7
int rand7()
{
   return (((rand() % 5 + 1) + (gi++ % 7)) % 7) + 1;
}

//call this seed before rand7
//maybe it's not best seed, if yo have any good idea tell me please
//and thanks JiminP again, he remind me to do this
void srand7()
{
    int i, n = time(0);
    for (i = 0; i < n % 7; i++)
        rand7();
}

void main(void)
{
    unsigned int result[10] = {0};
    int k;

    srand((unsigned int)time(0)); //initialize the seed for rand
    srand7() //initialize the rand7

    for (k = 0; k < 100000; k++)
        result[rand7() - 1]++;

    for (k = 0; k < 7; k++)
        printf("%d : %.05fn", k + 1, (float)result[k]/100000);
}