I'm trying to figure out how I can use recursion to do n-level nested for loops. For example, if n=3, there would be 3 'levels'
for(z=0;z<6;z++){
for(y=0;y<6;y++){
for(x=0;x<6;x++){
if (z+y+x==f){
//do something
}
}
}
}
and so on.
I can't seem to figure out how I would be able to place the if loop in the last for loop and how I can access the variables of previous for loops from the if statement. I know that the question of variable nested loops has been asked alot of times, and I have looked through all of them. But none seem to help me.
Could someone present an easy way of using recursion to achieve this, keeping in mind that I'm still a beginner in c++, to point me in the right direction?
The use case is as follows:
Write a program to input the number of dice m. The program will output the total number of possible cases, the number of possible cases for each possible n and the n with the highest probability. Note: only one input m is read in. n is computed by the program
Example if user enters m=2 then program should output
The total number of possible cases is 36.
The possibilities are
2 1
3 2
4 3
.
.
.
12 1
Here's an example in plain old C++. First I make a vector of the ranges for each dimension called maxes
. if the sum of all indices are 2 then I print did something.
In the example I loop z from 0 to 1, y from 0 to 2, x from 0 to 3
You can for sure make this more neat.
Here goes:
#include <iostream>
#include <vector>
using namespace std;
int f(){
return 2 ;
}
void inner(int depth,vector<int> & numbers,vector<int> & maxes){
if (depth>0){
for(int i=0;i<maxes[depth-1];i++){
numbers[depth-1]=i;
inner(depth-1, numbers,maxes) ;
}
}else{
// calculate sum of x,y,z:
cout << "values are ";
for(int i=0;i<numbers.size();i++){
cout <<numbers[i]<<" ";
}
int thesum(0);
for(int i=0;i<numbers.size();i++){
thesum+=numbers[i];
}
if (thesum==f()){
cout << "did something! ";
}
cout<<endl;
}
}
void donest(){
vector<int> numbers;
numbers.resize(3);
vector<int> maxes;
maxes.push_back(4);
maxes.push_back(3);
maxes.push_back(2);
inner(numbers.size(),numbers,maxes);
}
int main(){
donest();
}
result:
values are 0 0 0
values are 1 0 0
values are 2 0 0 did something!
values are 3 0 0
values are 0 1 0
values are 1 1 0 did something!
values are 2 1 0
values are 3 1 0
values are 0 2 0 did something!
values are 1 2 0
values are 2 2 0
values are 3 2 0
values are 0 0 1
values are 1 0 1 did something!
values are 2 0 1
values are 3 0 1
values are 0 1 1 did something!
values are 1 1 1
values are 2 1 1
values are 3 1 1
values are 0 2 1
values are 1 2 1
values are 2 2 1
values are 3 2 1