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simple C++ help please

Started by M0o Jul 8, 2011 at 4:50 PM 4 replies 2k views

Original Post

Jul 8, 2011 at 4:50 PM

Hey, im new to C++ and learn it through a book, anyways iv been set a task to rewrite a game "guess my number" where i have to make the computer guess the users number but i get stuck in a loop and i cant see why its really bugging me and i know its going to be the silliest thing...

[size="1"]// Guess My Number
// The classic number guessing game

[size="1"]#include
#include
#include

[size="1"]using namespace std;

[size="1"]int main()
{

srand(time(0)); // seed random number generator

int theNumber;

cout << "\nPlease enter a number between 1-100 for the computer to guess: ";
cin >> theNumber;

int tries = 0, computerGuess;

do
{
int computerGuess = rand() % 100 + 1;

cout << "The computers guess: ";
cout << computerGuess;
++tries;

[size="1"] if (computerGuess > theNumber)
cout << " Too high!\n\n";

if (computerGuess < theNumber)
cout << " Too low!\n\n";

}while (computerGuess != theNumber);

[size="1"] cout << "\nThe computer got your number in " << tries << " guesses!\n";

[size="1"] return 0;
}

MichaelNett

Jul 8, 2011 at 4:55 PM

That's possible. You never make sure that the number entered by the user is actually in the range of numbers that the computer could guess (which is between 1 and 100).

Texus

Jul 8, 2011 at 5:05 PM

This line is wrong:


 int computerGuess = rand() % 100 + 1;

You are redefining computerGuess.
Inside the do loop it will be a number, but when checking if it is different from theNumber, it will be 0 again.

You should leave the "int" on that line.

M0o

Jul 8, 2011 at 5:06 PM

That's possible. You never make sure that the number entered by the user is actually in the range of numbers that the computer could guess (which is between 1 and 100).

what do you mean? i tell the user to pick a number between 1-100 and the computer picks a random number between 1-100 but after the computer get the right number the loop dosent end.

M0o

Jul 8, 2011 at 5:08 PM

This line is wrong:
int computerGuess = rand() % 100 + 1;
You are redefining computerGuess.
Inside the do loop it will be a number, but when checking if it is different from theNumber, it will be 0 again.

You should leave the "int" on that line.

ahhhh i see now thanxs alot i knew it would be something silly i just thought i would have to set as int but i see now why i dont. :)

thanx for the help

fastcall22

Jul 8, 2011 at 9:18 PM

Just to clarify: The problem you're experiencing is called variable shadowing


 #include <iostream>
 
 using namespace std;
 
 int main() {
 int var = 1;
 cout << var << endl;
 
 do {
 cout << var << endl;
 
 int var = 2; // var shadows the "var" outside this scope
 cout << var << endl;
 } while ( false );
 
 cout << var << endl;
 }

Output:

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