Thread: speeding up nested for loop

ok, I have 3 nested for loops and I want to start at a particular point in the loop. what recommendations can you give me?

here is a sample code:

Code:

int main()
{
 int a,b,c,d;
 for(a=0;a<10;a++)
  for(b=0;b<10;b++)
   for(c=0;c<10;c++)
    for(d=0;d<10;d++)
     {
      if((a==0)&&(b==0)&&(c==0)&&(d==0))
      {
       a=1,b=2,c=3,d=4;
      }
      cout<a<<b<<c<<d;
     }
}

in my sample code, I have 3 nested for loops and it prints from "1234" to "9999" because I added an if statement to change some values. however, the if statement would slow down the nested for loops because it would be checked every time during a loop. any suggestion on another solution?

can the use of static work for this situation? if so, how?

what if you nested the if in another if that skiped that later after d clicked for however many number of times?

betazep, I think your solution is wrong.

the "for(b=2;b<=9;... " will make b start from 2 and ignore 1.

If 1234->9999 is required something like this should work -

Code:

#include <iostream>
using namespace std;

int main()
{
 int a,b,c,d;
 for(a=1;a<10;a++)
	 for(a==1?b=2:b=0;b<10;b++)
		 for(a==1&&b==2?c=3:c=0;c<10;c++)
			 for(a==1&&b==2&&c==3?d=4:d=0;d<10;d++)
			{		
				cout<<a<<b<<c<<d<<endl;
			 }
}

Sorensen, the code you gave would cost more time because the "?" will compare values for every pass in the nested loop.

the if statement from the first post is likely to finish the nested loop at a faster time. I also thought of something. can this possibly work?

Code:

int main()
{
 int a,b,c,d;
 for(a=0, static a=1;  a<10;  a++)
  for(b=0, static b=2;  b<10;  b++)
   for(c=0, static c=3;  c<10;  c++)
    for(d=0; static d=4; d<10;  d++)
      cout<a<<b<<c<<d;
}

>Sorensen, the code you gave would cost more time because the "?" will compare values for every pass in the nested loop.

No it won't. Do variables get initialised every pass of the for loop?

Ach soren beat me to it. But my post of the solutionis higher up and better documented so

Yeah unregged, like I said in MY post

This makes the test occur only once every tenth, twice every hundredth, and thrice every thousandth iteration, rather than every single iteration.