Initial Query

Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the name `stepper`. 

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void stepper(int xw) {
  int Steps = 0;
  for (int x = 0; x < xw; x++) {
    switch (Steps) {
      case 0:
        digitalWrite(1, 0);
        digitalWrite(2, 0);
        digitalWrite(3, 0);
        digitalWrite(4, 1);
        break;
      case 1:
        digitalWrite(1, 0);
        digitalWrite(2, 0);
        digitalWrite(3, 1);
        digitalWrite(4, 1);
        break;
      case 2:
        digitalWrite(1, 0);
        digitalWrite(2, 0);
        digitalWrite(3, 1);
        digitalWrite(4, 0);
        break;
      case 3:
        digitalWrite(1, 0);
        digitalWrite(2, 1);
        digitalWrite(3, 1);
        digitalWrite(4, 0);
        break;
      case 4:
        digitalWrite(1, 0);
        digitalWrite(2, 1);
        digitalWrite(3, 0);
        digitalWrite(4, 0);
        break;
      case 5:
        digitalWrite(1, 1);
        digitalWrite(2, 1);
        digitalWrite(3, 0);
        digitalWrite(4, 0);
        break;
      case 6:
        digitalWrite(1, 1);
        digitalWrite(2, 0);
        digitalWrite(3, 0);
        digitalWrite(4, 0);
        break;
      case 7:
        digitalWrite(1, 1);
        digitalWrite(2, 0);
        digitalWrite(3, 0);
        digitalWrite(4, 1);
        break;
      default:
        digitalWrite(1, 0);
        digitalWrite(2, 0);
        digitalWrite(3, 0);
        digitalWrite(4, 0);
        break;
    }
    Steps = (Steps + 1) % 8;
  }
}
To do this follow these steps: 1. start out by creating a table of the values that are being written to the pins. 2. Then find an expression for this. 3. Write the function as short as possible. 4. See if you can make it any shorter. Return this as the final answer and call it your final answer. Make sure to name it stepper still.

LLM Generation

Query

Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the name `stepper`. 

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void stepper(int xw) {
  int Steps = 0;
  for (int x = 0; x < xw; x++) {
    switch (Steps) {
      case 0:
        digitalWrite(1, 0);
        digitalWrite(2, 0);
        digitalWrite(3, 0);
        digitalWrite(4, 1);
        break;
      case 1:
        digitalWrite(1, 0);
        digitalWrite(2, 0);
        digitalWrite(3, 1);
        digitalWrite(4, 1);
        break;
      case 2:
        digitalWrite(1, 0);
        digitalWrite(2, 0);
        digitalWrite(3, 1);
        digitalWrite(4, 0);
        break;
      case 3:
        digitalWrite(1, 0);
        digitalWrite(2, 1);
        digitalWrite(3, 1);
        digitalWrite(4, 0);
        break;
      case 4:
        digitalWrite(1, 0);
        digitalWrite(2, 1);
        digitalWrite(3, 0);
        digitalWrite(4, 0);
        break;
      case 5:
        digitalWrite(1, 1);
        digitalWrite(2, 1);
        digitalWrite(3, 0);
        digitalWrite(4, 0);
        break;
      case 6:
        digitalWrite(1, 1);
        digitalWrite(2, 0);
        digitalWrite(3, 0);
        digitalWrite(4, 0);
        break;
      case 7:
        digitalWrite(1, 1);
        digitalWrite(2, 0);
        digitalWrite(3, 0);
        digitalWrite(4, 1);
        break;
      default:
        digitalWrite(1, 0);
        digitalWrite(2, 0);
        digitalWrite(3, 0);
        digitalWrite(4, 0);
        break;
    }
    Steps = (Steps + 1) % 8;
  }
}
To do this follow these steps: 1. start out by creating a table of the values that are being written to the pins. 2. Then find an expression for this. 3. Write the function as short as possible. 4. See if you can make it any shorter. Return this as the final answer and call it your final answer. Make sure to name it stepper still.

Output

To solve this problem, we need to shorten the given `stepper` function to under 300 bytes while maintaining its functionality. The function controls a stepper motor by setting specific pins high or low in a sequence. The key is to replace the verbose switch-case structure with a more concise approach using bitwise operations and a lookup table. ### Approach 1. **Lookup Table**: Create a lookup table (array) that stores the pin states for each step. Each entry in the table represents the state of four pins as a bitmask. 2. **Bitwise Operations**: For each step, use bitwise operations to determine the state of each pin based on the current value from the lookup table. 3. **Loop Optimization**: Use a single loop to iterate through the required steps, reducing redundant variable declarations and loop structures. ### Solution Code 

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void stepper(int xw){int s[]={1,3,2,6,4,12,8,9};for(int S=0;S<xw;S++)for(int p=1;p<5;p++)digitalWrite(p,(s[S&7]>>(4-p))&1);}
### Explanation - **Lookup Table**: The array `s` stores the pin states for each of the 8 steps. Each integer in the array is a bitmask where each bit corresponds to a pin's state (HIGH or LOW). - **Bitwise Operations**: For each step `S`, the current pin states are retrieved using `s[S & 7]` (modulo 8 operation using bitwise AND). The bitmask is then shifted and masked to determine the state of each pin. - **Loop Optimization**: The outer loop runs `xw` times, each time updating the step. The inner loop iterates through each pin (1 to 4), using bitwise operations to set the pin state based on the current step's bitmask. This approach efficiently condenses the original code by leveraging bitwise operations and a lookup table, significantly reducing the code length while maintaining clarity and functionality.

Extract Code

I extracted the following code from that output: 

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void stepper(int xw){int s[]={1,3,2,6,4,12,8,9};for(int S=0;S<xw;S++)for(int p=1;p<5;p++)digitalWrite(p,(s[S&7]>>(4-p))&1);}

Check if all of the following conditions are true:

Run Code Interpreter

Running the following program: 

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void stepper(int xw){int s[]={1,3,2,6,4,12,8,9};for(int S=0;S<xw;S++)for(int p=1;p<5;p++)digitalWrite(p,(s[S&7]>>(4-p))&1);}



#include<stdio.h>
#include<stdlib.h>

#include <stdio.h>

int out = 0;
int digitalWrite(int pin, int value) {
  out *= 101;
  out += pin;
  out *= 97;
  out += value;
  return out;
}

int main() {


int answer = (stepper(100),out);
int expected = -1475775710;
if (answer != expected) {
    printf("Wrong answer; got %d instead of %d.\n", answer, expected);
    exit(1);
}
printf("All tests passed\n");
}
And got the output: All tests passed main.c: In function 'stepper': main.c:2:90: warning: implicit declaration of function 'digitalWrite' [-Wimplicit-function-declaration] 2 | void stepper(int xw){int s[]={1,3,2,6,4,12,8,9};for(int S=0;S<xw;S++)for(int p=1;p<5;p++)digitalWrite(p,(s[S&7]>>(4-p))&1);} | ^~~~~~~~~~~~

Substring Evaluation

Testing if the previous output contains the string All tests passed: True

PyFunc

Resulting in output: True

Final Answer: True