programming languages – How to prove that replacing a character in a string in both C and JavaScript is equivalent?

I would like to try some different proofs, specifically in proving equivalence of the implementation of some feature in two different programming languages (C and JS in this question).

This is about proving that replacing one character in a string is equivalent in C and JS.

In JS, for example, strings are immutable, while in C, strings are mutable. So in JS you might have to do this:

functioni replaceAt(string, index, replacement) {
  return string.substr(0, index) + replacement + string.substr(index + replacement.length)

While in C you might just do something like this:


main() {
  char string(11) = "hello world";
  string(1) = 'i';
  printf("%s", string);
  return 0;

Basically, I am trying to come up with an example where, the perceived effect or desired outcome is for all intents and purposes the same. That is, the end result is that the character was replaced at a specific position (the same position in each language). Even though in one language the string was mutable, while in the other, it was immutable. What needs to be taken into account here to make a proof saying these are equivalent? How do we capture the notion of “partial equivalence” or “perceived equivalence”? (By that I mean, the outcome is roughly the same, so we want to make a proof statement that these are the same with regard to some spec).

dnd 5e – I am trying to play d&d and am making my first character sheet and I finished everything but one part

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like – Mysql, Getting all rows in which field ends in a specific character, and another field exists that is the same but doesn’t end in that character

I need to get all rows which end in a specific character, P for example, but in which a similar key sans the P exists. I have no idea how to approach this one in MySQL.

This is very small example, my actual data is huge with other columns also.

|    key     |
| value_100  |
| value_100P |
| value_101  |
| value_101  |
| value_102  |
| value_102P |
| value_103P |
| value_104P |

The query would output,

|    key     |
| value_100P |
| value_102P |

Regarding skills and character creation [closed]

I am a 1st level sorcer with an Intelligence of 10. How many skill points do I have to work with?

c# – Unity 2D: Dealing damage when character is crushed between two solid objects

Whats the best approach to dealing damage to a player when they get stuck between two solid objects? For instance, I’m trying to make moving platforms that the player can ordinarily touch. It’s only when the player is caught in-between the moving platform and the ceiling, for example, that damage is dealt or the player dies.

So, what would be the best way to approach this? Thanks in advance!

Is there any better way to stun a character in Roblox?

In Elemental Battlegrounds, punches stun the character, nicely and smoothly. My best way to stun players is this trash:

HitChar:SetPrimaryPartCFrame(*CFrame.Angles(math.pi/2, Orientation.Y, Orientation.Z))

Is there any better way? I want it to look natural, and not look like teleporting to a sideways position.

dnd 3.5e – When creating a character above 1st level, can you give them the effects of spellcasting services?

Page 199 of the DMG explains how new characters can start with magic items, even those they choose to make themselves (with the assumption these items were created some time before the character became a PC)

But let’s say a non-spellcaster wants to give themselves an extra point to an ability score. If they have 27,500 gp, they could start with a Manual of Quickness of Action and either use it immediately or possibly say they’ve used it already and begin with an inherent +1 bonus to Dexterity.

That book costs 27,500 gp. Using the formula on page 129 of the PHB, however, it would only cost 26,530 gp to have a 17th-level wizard cast wish on them as a service. For an 8th-level character (or a higher-level character with lots of other gear), that’s the difference between getting the bonus, and not.

Can the character simply decide to begin with this effect present (or a different spell with a permanent duration, like enlarge person+permanency, since 9th-level wizards are easy to find in large cities) and 26,530 gp less, or since the DMG only describes starting with magic items, must they spend 27,500 gp for the magic item?

sql server – conversion failed when converting date and/or time from character string c#

Action Method:

PayTns std = new PayTns();
std.C_Group = fc(“C_Group”);
std.Date = Convert.ToDateTime(fc(“Date”));
std.C_Name = fc(“C_Name”);
std.D_Group = fc(“D_Group”);
std.D_Name = fc(“D_Name”);
std.Amount = Convert.ToInt32(fc(“Amount”));
std.Remark = fc(“Remark”);
if (D_flag == “true”)
std.D_Flag = true;
std.D_Flag = false;
std.T_No = Convert.ToInt32(fc(“T_No”));
TempData(“msg”) = “Data Inserted”;

Data Connection:

SqlCommand com = new SqlCommand(“Master_PayTns_Add”, con);
com.CommandType = CommandType.StoredProcedure;
com.Parameters.AddWithValue(“@Date”, ie.Date);
//com.Parameters.AddWithValue(“@A_GRef”, ie.A_GRef );
com.Parameters.AddWithValue(“@C_Group”, ie.C_Group);
com.Parameters.AddWithValue(“@C_Name”, ie.C_Name);
com.Parameters.AddWithValue(“@D_Group”, ie.D_Group);
com.Parameters.AddWithValue(“@D_Name”, ie.C_Name);
com.Parameters.AddWithValue(“@Amount”, ie.Amount);
com.Parameters.AddWithValue(“@Remarks”, ie.Remark);
com.Parameters.AddWithValue(“@D_FLag”, Convert.ToBoolean(ie.D_Flag));
com.Parameters.AddWithValue(“@T_No”, ie.T_No);


How do I replace a paragraph break (i.e. Enter) with a Shift+Enter character in Google Docs?

I have read Syntax for Unicode characters in regexes in Google Sheets? to no avail.

c# – How to make a character move with WASD in unity

So, I have been trying for so long to make a WASD movement script, and I can’t. It has come to the point that I am even getting the code off the official Unity site.

And here is the code:

using UnityEngine;
using System.Collections;

// This script moves the character controller forward
// and sideways based on the arrow keys.
// It also jumps when pressing space.
// Make sure to attach a character controller to the same game object.
// It is recommended that you make only one call to Move or SimpleMove per frame.

public class ExampleClass : MonoBehaviour
    CharacterController characterController;

    public float speed = 6.0f;
    public float jumpSpeed = 8.0f;
    public float gravity = 20.0f;

    private Vector3 moveDirection =;

    void Start()
        characterController = GetComponent<CharacterController>();

    void Update()
        if (characterController.isGrounded)
            // We are grounded, so recalculate
            // move direction directly from axes

            moveDirection = new Vector3(Input.GetAxis("Horizontal"), 0.0f, Input.GetAxis("Vertical"));
            moveDirection *= speed;

            if (Input.GetButton("Jump"))
                moveDirection.y = jumpSpeed;

        // Apply gravity. Gravity is multiplied by deltaTime twice (once here, and once below
        // when the moveDirection is multiplied by deltaTime). This is because gravity should be applied
        // as an acceleration (ms^-2)
        moveDirection.y -= gravity * Time.deltaTime;

        // Move the controller
        characterController.Move(moveDirection * Time.deltaTime);

Then I have imported it to Unity, then it says ‘GrapplingHook.cs is not defined’ when I haven’t even got a GrapplingHook.cs, so why is it doing it?

So why does this do that?