Initial Query

Code golf this function to be a lot shorter. You only get points if it's <200 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;
  }
}

LLM Generation

Query

Code golf this function to be a lot shorter. You only get points if it's <200 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;
  }
}

Output

To solve this problem, we need to optimize a function that controls a stepper motor by reducing the code length to under 200 bytes. The original function uses a switch-case structure to set the motor pins to specific states in each step. The goal is to replace this verbose structure with a more concise and efficient approach. ### Approach The key insight is to recognize that each step of the motor can be represented as a 4-bit value, where each bit corresponds to a motor pin. By storing these bit values in an array, we can iterate through the array and use bitwise operations to set the pins correctly for each step. This approach eliminates the need for a lengthy switch-case structure and reduces the code significantly. ### Solution Code 

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void stepper(int xw){int a[]={1,3,2,6,4,12,8,9};for(int x=0;x<xw;x++)for(int j=4;j--;)digitalWrite(4-j,(a[x&7]>>j)&1);}
### Explanation 1. **Array Initialization**: The array `a` stores the 4-bit values for each of the 8 steps required by the stepper motor. Each value in the array represents the state of the motor pins (1 to 4) for a specific step. 2. **Loop Through Steps**: The outer loop runs `xw` times, each iteration corresponding to one step of the motor. 3. **Bitwise Operations**: The inner loop iterates over each pin (1 to 4) using a reverse index. For each pin, the corresponding bit from the current step's value is extracted using bitwise operations. The `digitalWrite` function sets the pin state based on this bit value. 4. **Modulo Operation**: The modulo operation `x & 7` (equivalent to `x % 8`) ensures that the step index cycles through 0 to 7, covering all 8 steps of the motor. This approach efficiently reduces the code length by leveraging bitwise operations and array indexing, achieving the desired functionality in a concise manner.

Extract Code

I extracted the following code from that output: 

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void stepper(int xw){int a[]={1,3,2,6,4,12,8,9};for(int x=0;x<xw;x++)for(int j=4;j--;)digitalWrite(4-j,(a[x&7]>>j)&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 a[]={1,3,2,6,4,12,8,9};for(int x=0;x<xw;x++)for(int j=4;j--;)digitalWrite(4-j,(a[x&7]>>j)&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:2:87: warning: implicit declaration of function 'digitalWrite' [-Wimplicit-function-declaration] 2 | void stepper(int xw){int a[]={1,3,2,6,4,12,8,9};for(int x=0;x<xw;x++)for(int j=4;j--;)digitalWrite(4-j,(a[x&7]>>j)&1);} | ^~~~~~~~~~~~

Substring Evaluation

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

PyFunc

Resulting in output: True

Final Answer: True