so if you put    

float a = random(0,3);

it would keep on generating random numbers between 0 and 3.

But I only want it to generate one number what do i do?

My code looks like:

1.     float a = random(0,3);
2.     if(a < 1);
3.     {
4.     
5.      .....
6. ......
7.        
8.       }
9.      
10.      
11.        if((a >= 1)&&(a < 2));
12.     {
13. .....
14. .....
15.     }
16.    
17.      if((a >= 2)&&(a  <= 3));
18.     {
19. ....
20. ....
21.     }
22.