Trying to create lotto game, having problems with execution and compilation - c++

Question

im trying to set up a lottery game that asks for input from the user 3 times and compares this to numbers drawn by the random array. if any of these user numbers match a number in the array, the program should print out the numbers that matched.
ive tried to use while loops in my main function to control the flow but im still having issues with compilation
#include<iostream>
#include <ctime>
#include "array.h"
using std::cout; using std::cin; using std::endl;
const int sizeofArray = 20;
void assign(int wins[], int sizeofArray);
void draw(int sizeofArray, int wins[]);
bool check(int num1, int wins[], int sizeofArray);
void entry(int& userNum);
void printOut(int wins[], int num);
int main() {
srand(time(nullptr));
int user[sizeofArray];
cout << "Good luck with this weeks lotto drawing!" << endl;
int wins[sizeofArray];
assign(wins, sizeofArray);
draw(sizeofArray, wins);
int userInput;
entry(userInput);
bool win = check(userInput, wins, sizeofArray);
if (win)
cout << "you have won!" << endl;
printOut(wins, sizeofArray);
}
void assign(int wins[], int sizeofArray) {
for (int i = 0; i < sizeofArray; ++i)
wins[i] = 0;
}
void draw(int sizeofArray, int wins[]) {
int number = 0;
while (number < sizeofArray) {
int number = rand() % 100 + 1;
if (!check(number, wins, sizeofArray)) {
wins[number] = number;
number++;
}
}
}
bool check(int num1, int wins[], int sizeofArray) {
for (int j = 0; j < sizeofArray; j++) {
if (wins[j] == num1)
return true;
}
return false;
}
void entry(int& userNum) {
int j;
cout << "Enter your lottery number guess: ";
cin >> userNum;
cout << "Your number was " << userNum << endl;
}
void printOut(int wins[], int num) {
cout << "Winning numbers in lottery are" << endl;
for (int j = 0; j < num; ++j) {
cout << wins[j] << " ";
}
}
i

Answer 1

Your draw method is going to loop infinitely since you declared the condition variable twice which causes the ++ operator to be applied on the wrong variable
void draw(int sizeofArray, int wins[]) {
int number = 0; // <--- HERE
while (number < sizeofArray) {
int number = rand() % 100 + 1; // <--- AND HERE
if (!check(number, wins, sizeofArray)) {
wins[number] = number;
number++; //This will increase the inner variable number not the outer one
}
}
}
to fix it just change the name of your variable
void draw(int sizeofArray, int wins[]) {
int counter = 0; <---
while (counter < sizeofArray) { <---
int number = rand() % 100 + 1;
if (!check(number, wins, sizeofArray)) {
wins[number] = number;
counter++; <---
}
}
}

Answer 2

Let's take a look at draw():
void draw(int sizeofArray, int wins[]) {
int number = 0; //First variable of name number
while (number < sizeofArray) {
//new variable with name number is introduced, it shadows the first one
int number = rand() % 100 + 1; //<-----------------------+
if (!check(number, wins, sizeofArray)) { // |
wins[number] = number; // |
number++; //Here you actually increase this variable-+
}
}
}
So called shadowing occurs here and the outer int number is never modified inside the loop. Just rename one of them and you should be fine.
If you want to read more about this, take a look here.