CODEWITHSUNDEEP
c++loops
user11869427
user11869427

Reputation:

Infinite outputs of an if-else/while loop?

I'm a beginner programmer in C++ trying to create this practice guess-the-number game that needs to fulfill some requirements. These are:

  1. Use 'flush' (I don't know what this is, help?)
  2. Exit the game once the number has been guessed
  3. Exit the game once a maximum of 10 guesses have been exceeded

But the problem right now is that when I enter a number, it tells me whether the entered number is higher or lower than the randomly generated correct number continuously. So if it's lower, the output is 'lowerlowerlowerlowerlowerlowerlowerlowerlower' and so forth. I don't know what I did wrong?

Here is my code. (X = randomly generated number, Y = guess, Z = # of guesses)

int main() {
  int x , y, z;
  x = rand() % 1000 + 1;
  std::cin>>y;
  do{
    if (y > x){
      std::cout<<"higher"<< std::endl;
      z++;
    } else if (y < x) {
      std::cout<<"lower"<< std::endl;
      z++;
    } else if (y == x) {
      std::cout<<"correct"<< std::endl;
    }
  } while (y != x && z < 11);
  return 0;
}

Upvotes: 0

Views: 115

Answers (5)

Grzegorz Małyska
Grzegorz Małyska

Reputation: 97

You're doing wrong a few things:

  • As you must use flush operation explicitly, you must use std::cout << std::flush; somewhere.
  • You need to get input from the user inside do-while loop body.
  • You need to initialize random number generator first before using it.
  • You need to initialize z variable to 0, because you've undefined behaviour - you're incrementing the variable which has undefined value (not initialized earlier).

Here is your code with these fixes:

#include <iostream>
#include <ctime>

int main() {
    int x, y, z = 0;
    srand(time(NULL));
    x = rand() % 1000 + 1;

    std::cout << x << std::endl;

    do {
        std::cin >> y;
        if(y > x) {
            std::cout << "higher" << std::endl;
            z++;
        } else if(y < x) {
            std::cout << "lower" << std::endl;
            z++;
        } else {
            std::cout << "correct" << std::endl;
        }
        std::cout << std::flush;
    } while(y != x && z <= 10);
    return 0;
}

You said you don't know what is a flush operation. This is the operation of empting output buffer (used by std::cout object internally). Normally you don't need to explicitly flush output buffer, but if you need so...

Upvotes: 0

Nikhil Badyal
Nikhil Badyal

Reputation: 1697

  1. Just take input inside do-while loop.
  2. Another issue initializes Z with zero. It is default initialized and can have any value.
  3. Suggestion initialize random seed: 
srand (time(NULL)); // it will give 'x' every time a different value.
int  z=0; // Dont forget to do this thing.

do{
    cout<<"Enter number - "; // This thing your are missing.
    std::cin>>y;
    if (y > x){
      std::cout<<"higher"<< std::endl;
      z++;
    }
    else if (y < x) {
      std::cout<<"lower"<< std::endl;
      z++;
    }
    else if (y == x) {
      std::cout<<"correct"<< std::endl;
    }
  } while (y != x && z < 11);
  return 0;

Upvotes: 0

Soheil Armin
Soheil Armin

Reputation: 2795

Put your std::cin into the loop. You also need to set z at first and add it by 1 every time the loop runs.

int main() {
  srand (time(NULL));
  int x , y, z;
  x = rand() % 1000 + 1;
  z = 0;

  do{
 std::cin>>y;
    if (y > x){
      std::cout<<"higher"<< std::endl;

    } else if (y < x) {
      std::cout<<"lower"<< std::endl;

    } else if (y == x) {
      std::cout<<"correct"<< std::endl;
    }
  } while (y != x && z++ < 9);
  return 0;
}

Upvotes: 1

Oblivion
Oblivion

Reputation: 7374

You have undefined behavior:

z++;

z is used before initialization.

Upvotes: 0

Spinkoo
Spinkoo

Reputation: 2080

1- the variable z is not initialized

2-you are supposed to read the input everytime you loop i guess ( to read the guess )? like this 

do{
   std::cin>> y ;
   // the rest of your loop
while(your condition);

Note : you should initialize random seed before you use your random function : 

srand (time(NULL));

Upvotes: 0

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