**Tags**

http://stackoverflow.com/questions/137783/expand-a-random-range-from-15-to-17

int rand7()

{

int vals[5][5] = {

{ 1, 2, 3, 4, 5 },

{ 6, 7, 1, 2, 3 },

{ 4, 5, 6, 7, 1 },

{ 2, 3, 4, 5, 6 },

{ 7, 0, 0, 0, 0 }

};

int result = 0;

while (result == 0)

{

int i = rand5();

int j = rand5();

result = vals[i-1][j-1];

}

return result;

}

or

int i;

do

{

i = 5 * (rand5() – 1) + rand5(); // i is now uniformly random between 1 and 25

} while(i > 21);

// i is now uniformly random between 1 and 21

return i % 7 + 1; // result is now uniformly random between 1 and 7