#I think I am doing rng wrong

15 messages · Page 1 of 1 (latest)

barren valve
#

Hello everyone!
I have been working on making a portfolio of projects as an exercise to improve my skills with cpp.
I coded this simple rock paper scissors games this morning.
The code runs fine, its just that the rng seems to be completely of, with the player always losing.
I think that I am either doing rng wrong, or have an error in my logic that I have not spotted.
Thanks in advance,
I2P

#include<random>
#include<iostream>

void round()
{
int selection;
std::cin>>selection;

std::random_device dev;
std::mt19937 rng(dev());
std::uniform_int_distribution<std::mt19937::result_type>dist3(1,3);

bool win=false;
int opponent=dist3(rng);

if(selection==opponent)
{
    std::cout<<"tie!"<<std::endl;
}
else
{
    switch(selection)
    {
        case 1:
            if(opponent==3)
            {
                std::cout<<"you win!"<<std::endl;
                win=true;
            }

        case 2:
            if(opponent==1)
            {
                std::cout<<"you win!"<<std::endl;
                win=true;
            }

        case 3:
            if(opponent==2)
            {
                std::cout<<"you win!"<<std::endl;
                win=true;
            }
    }
    if(!win)
    {
        std::cout<<"you lose!"<<std::endl;
    }
}

}

int main()
{
while(true)
{
round();
}
return 0;
}

velvet hollowBOT
#

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calm vine
velvet hollowBOT
#

Hello everyone!
I have been working on making a portfolio of projects as an exercise to improve my skills with cpp.
I coded this simple rock paper scissors games this morning.
The code runs fine, its just that the rng seems to be completely of, with the player always losing.
I think that I am either doing rng wrong, or have an error in my logic that I have not spotted.
Thanks in advance,
I2P

#include <iostream>
#include <random>

void round() {
  int selection;
  std::cin >> selection;

  std::random_device dev;
  std::mt19937 rng(dev());
  std::uniform_int_distribution<std::mt19937::result_type> dist3(1, 3);

  bool win = false;
  int opponent = dist3(rng);

  if (selection == opponent) {
    std::cout << "tie!" << std::endl;
  } else {
    switch (selection) {
      case 1:
        if (opponent == 3) {
          std::cout << "you win!" << std::endl;
          win = true;
        }

      case 2:
        if (opponent == 1) {
          std::cout << "you win!" << std::endl;
          win = true;
        }

      case 3:
        if (opponent == 2) {
          std::cout << "you win!" << std::endl;
          win = true;
        }
    }
    if (!win) {
      std::cout << "you lose!" << std::endl;
    }
  }
}

int main() {
  while (true) {
    round();
  }
  return 0;
}
I2PTHEGREAT
Formatted by Chara_VerKys
calm vine
#

, with the player always losing.

barren valve
#

Sorry my mistake, meant to say never losing

velvet hollowBOT
barren valve
#

So is it just rng being weird or did I make a mistake in my code?

calm vine
#

wait

#

how did i even miss that

#

you not use break anywhere

#

xDDD

wanton lance
# barren valve Hello everyone! I have been working on making a portfolio of projects as an exer...

The error is in the switch statement. You need to break; at the end of each switch statement, like this:

        switch(selection)
        {
            case 1:
                if(opponent==3)
                {
                    std::cout<<"you win!"<<std::endl;
                    win=true;
                }
                break;
            case 2:
                if(opponent==1)
                {
                    std::cout<<"you win!"<<std::endl;
                    win=true;
                }
                break;
            case 3:
                if(opponent==2)
                {
                    std::cout<<"you win!"<<std::endl;
                    win=true;
                }
                break;
          }

Otherwise, when a case statement matches, all case statements after that will execute as well. For example if the user choice a value of 1, it will set win to true if the opponent has value 1, 2 or 3 (aka, all cases).

barren valve
#

!solved

velvet hollowBOT
#

Thank you and let us know if you have any more questions!

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