Return to Question

I have an array of elements:

int[] elem = new int[] {A, B, C};

I need to calculate the sum of ALL the combinations of those elements, where only some of the elements can be optionally selected. I will use the notation:

• {0,1} mean element can be selected or not
• {1} mean element is always selected.

Therefore, I need to calculate the following value, which could be something like:

result = {0,1}*A + {1}*B + {0,1}*C;

I have tried to use nested for loops, like so:

total = 0;
for (int i=0;i<2;i++)
    for (int j=1;j<2;j++) // notice I start at 1, not 0, because B is {1}
        for (int k=0;k<2;k++)
            total += i*A + j*B + k*C;

There are two problems with this:

• These nested for loops are rather cumbersome
• My example only has three elements, but the array could be of any size. For example, if the array had 10 elements, I would need to have 10 nested loops instead of three. I don't know to change the number of for loops based on the array size.

How would I iterate to get all sum values for all combinations in an arbitrary sized array?

I have an array of elements:

int[] elem = new int[] {A, B, C};

I need to calculate the sum of ALL the combinations of those elements, where only some of the elements can be optionally selected. I will use the notation:

• {0,1} mean element can be selected or not
• {1} mean element is always selected.

Therefore, I need to calculate the following value, which could be something like:

result = {0,1}*A + {1}*B + {0,1}*C;

I have tried to use nested for loops, like so:

for (int i=0;i<2;i++)
    for (int j=1;j<2;j++) // notice I start at 1, not 0, because B is {1}
        for (int k=0;k<2;k++)
            Console.Write( i*A + j*B + k*C );

There are two problems with this:

• These nested for loops are rather cumbersome
• My example only has three elements, but the array could be of any size. For example, if the array had 10 elements, I would need to have 10 nested loops instead of three. I don't know to change the number of for loops based on the array size.

How would I iterate to get all sum values for all combinations in an arbitrary sized array?

I have an array of elements.

int[] elem = new int[] {A, B, C, D, E};

I need to calculate ALL the combinations of those elements

result = {0,1}*A + {0,1}*B + {0,1}*C + {1}*D + {0,1}*E

{0,1} mean element can be selected or not
{1} mean element is always selected.

I could do something like

for (int i=0;i<2;i++)
    for (int j=0;j<2;j++)
        for (int k=0;k<2;k++)
            for (int l=1;l<2;l++)
               for (int m=0;m<2;m++)
                  result i*A + j*B + k*C + l*D + m*E

There are two problems with this:

• These nested for loops are rather cumbersome
• The example has five elements in the elem array and the nested loops to handle it - how do you handle it if elem array was determined at runtime? It could be five, or six, or ten or whatever elements in the array. The nested loops only work for one array size.

So how should I iterate to get all sum values for all combinations in an arbitrary sized array?

I have an array of elements:

int[] elem = new int[] {A, B, C};

I need to calculate the sum of ALL the combinations of those elements, where only some of the elements can be optionally selected. I will use the notation:

• {0,1} mean element can be selected or not
• {1} mean element is always selected.

Therefore, I need to calculate the following value, which could be something like:

result = {0,1}*A + {1}*B + {0,1}*C;

I have tried to use nested for loops, like so:

total = 0;
for (int i=0;i<2;i++)
    for (int j=1;j<2;j++) // notice I start at 1, not 0, because B is {1}
        for (int k=0;k<2;k++)
            total += i*A + j*B + k*C;

There are two problems with this:

• These nested for loops are rather cumbersome
• My example only has three elements, but the array could be of any size. For example, if the array had 10 elements, I would need to have 10 nested loops instead of three. I don't know to change the number of for loops based on the array size.

How would I iterate to get all sum values for all combinations in an arbitrary sized array?

I have an array of elements.

int[] elem = new int[] {A, B, C, D, E};

I need to calculate ALL the combinations of those elements

result = {0,1}*A + {0,1}*B + {0,1}*C + {1}*D + {0,1}*E

{0,1} mean element can be selected or not
{1} mean element is always selected.

I could do something like

for (int i=0;i<2;i++)
    for (int j=0;j<2;j++)
        for (int k=0;k<2;k++)
            for (int l=1;l<2;l++)
               for (int m=0;m<2;m++)
                  result i*A + j*B + k*C + l*D + m*E

There are two problems with this:

• These nested for loops are rather cumbersome
• The example has five elements in the elem array and the nested loops to handle it - how do you handle it if elem array was determined at runtime? It could be five, or six, or ten or whatever elements in the array. The nested loops only work for one array size.

So how should I iterate to get all values for an arbitrary sized array?

I have an array of elements.

int[] elem = new int[] {A, B, C, D, E};

I need to calculate ALL the combinations of those elements

result = {0,1}*A + {0,1}*B + {0,1}*C + {1}*D + {0,1}*E

{0,1} mean element can be selected or not
{1} mean element is always selected.

I could do something like

for (int i=0;i<2;i++)
    for (int j=0;j<2;j++)
        for (int k=0;k<2;k++)
            for (int l=1;l<2;l++)
               for (int m=0;m<2;m++)
                  result i*A + j*B + k*C + l*D + m*E

There are two problems with this:

• These nested for loops are rather cumbersome
• The example has five elements in the elem array and the nested loops to handle it - how do you handle it if elem array was determined at runtime? It could be five, or six, or ten or whatever elements in the array. The nested loops only work for one array size.

So how should I iterate to get all sum values for all combinations in an arbitrary sized array?