Use the modulo (%) operator to generate random numbers within a specific range.

Question

The example below generates whole numbers within a range of 1 to 6.
int main () {
for (int x = 1; x <= 10; x++) {
cout << 1 + (rand() % 6) << endl;
}
}

/* Output:
6
6
5
5
6
5
1
1
5
3
*/

but when i wish to use range between 2 to 9 .
the output becomes include 10.
how its possible??
explain???

Answer 1

Try this code
you should use this formula

from + (rand() % (to - from + 1))

https://code.sololearn.com/cQ2273i41tPS/?ref=app

Answer 2

rand % (max - min + 1) + min
This is the formula for random number generator in a specific range that I know and it really works.
Replace max with maximum range value and min with minimum range value

Answer 3

if (random number) % 9 's result is 8, output be 10 if u want specific range. minimum number is the number you are adding ( 3 + rand() % 9) <- in this example min. num. is 3. and the maximum number is (9 - 1) + 3 equals 11.

Edit:
If you ask why we are doing 9 - 1, because when you divide a number that can exactly be divided by 9 its reminder become 0. (simple math knowledge)

Answer 4

the code which you are using here is cout<<1+(rand()%6)<<endl
here what is happeng is that you get a number using rand function then you make reduce it to range 0 to 5 (modulo 6 contains 0,1,2,3,4,5) , then what ever the number is ,you are adding 1 to it.

similar is the case for 2-9 range, lets say rand function gave a number ' x ' and you module 9 converts it to 8 and you added 2 to it, this becomes 10