I am trying to make a lottery number generator. So I need 6 random numbers.
The current code below displays the same number 6 times. Thoughts?
#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
char userchoice;
int main()
{
cout<<"Welcome to The Lottery Wizard!"<<endl<<endl;
cout<<"This program will allow you to play the lottery from"<<endl;
cout<<"the comfort of your computer desk."<<endl<<endl;
cout << "Do you want to play the Lottery? (y = yes, n = no): ";
cin.sync();
cin.get(userchoice);
userchoice = tolower(userchoice); //convert user's answer to lowercase
while (userchoice != 'y' && userchoice != 'n')
{
cout << "Invalid response. Enter a y for yes or n for no: ";
cin.sync(); // clear out buffer
cin.clear(); // set read to good
cin.get(userchoice);
}
system("cls");
while (tolower(userchoice) == 'y')
{
cout<<"The six random lottery numbers are:";
int number_back;
srand( time (NULL) ); //gets seed from clock
number_back = rand() % 53 + 1; //formula for 1-53 random number
for (int count = 0; count < 6 ; count++)
cout<<number_back<<endl;
cout << "Do you want to play the Lottery? (y = yes, n = no): ";
cin.sync();
cin.get(userchoice);
userchoice = tolower(userchoice); //convert user's answer to lowercase
while (userchoice != 'y' && userchoice != 'n')
{
cout << "Invalid response. Enter a y for yes or n for no: ";
cin.sync(); // clear out buffer
cin.clear(); // set read to good
cin.get(userchoice);
}
}
system("cls");
cout<<"Thanks for playing"<<endl<<endl;
return 0;
}
cout << "Do you want to play? (y = yes, n = no): ";
cin.sync();
cin.get(userchoice);
userchoice = tolower(userchoice); //convert user's answer to lowercase
while (userchoice != 'y' && userchoice != 'n')
{
cout << "Invalid response. Enter a y for yes or n for no: ";
cin.sync(); // clear out buffer
cin.clear(); // set for a good read
cin.get(userchoice);
}
if (userchoice == 'n')
return 0;
1.
if ( option == 'y' )
2.
// what would i put here for continue?
3.
else if ( option == 'n' )
4.
exit(0); //that is correct right?
5.
else
6.
cout<<"You have entered an invalid choice, please try again";
cin>>option;
I just dont know what to put for continue, am I going the right way here?
So is there a way to do it to do this with making 'y' the only way to continue the program and 'n' to exit. Not y and other chars to continue and anything but y exit.
while (!cin || user_number < 1 || user_number > 100) //makes sure no non-integers are entered
{
cout << "Invalid value entered. Please enter an integer between 1 and 100: ";
cin.clear(); //reset the read to good
cin.sync(); //clear out the contents of the input buffer
cin >> user_number;
}
I need to prompt the user if they want to actually execute the program or not.
Like, "Do you want to run the program, y=yes and n=no"
Then user enters y or n and the program either runs or quits.
I was thinking that would be like:
char answer;
cout<<"Do you want to run the program, y=yes and n=no";
cin>>answer;
if
(answer=y)
//I don't know what to put here to execute the program
else
//Also don't know what to put here to quit
# include <string>
# include <iostream>
# include <cstdlib>
using namespace std;
int main()
{
string name;
string test1;
double score1;
string test2;
double score2;
string test3;
double score3;
cout << "Welcome to the Grade Calculator Machine. You will enter three test scores." <<endl;
cout << "The higher of the first two test grades will be added with the third test grade" <<endl;
cout << "to determine the final grade average for the course." <<endl<<endl;
cout <<"Enter the student's name:";
getline(cin, name);
cout <<"Please enter test score 1:";
cin >> test1;
score1 = strtod (test1.c_str (), NULL);
if (score1 > 0)
cout << "Score is " << score1 << endl;
else if (score1 < 0)
cout << "Invalid. You entered a negative number." << endl;
else
cout << "You entered either 0 or an invalid number." << endl;
cout <<"Please enter test score 2:";
cin >> test2;
score2 = strtod (test2.c_str (), NULL);
if (score2 > 0)
cout << "Score is " << score2 << endl;
else if (score2 < 0)
cout << "Invalid. You entered a negative number." << endl;
else
cout << "You entered either 0 or an invalid number." << endl;
cout <<"Please enter test score 3:";
cin >> test3;
score3 = strtod (test3.c_str (), NULL);
if (score3 > 0)
cout << "Score is " << score3 << endl;
else if (score3 < 0)
cout << "Invalid. You entered a negative number." << endl;
else
cout << "You entered either 0 or an invalid number." << …
string test1;
double score1;
cout <<"Please enter test score 1:";
cin >> test1;
score1 = strtod (test1.c_str (), NULL);
if (score1 > 0)
cout << "Score is " << score1 << endl;
else if (score1 < 0)
cout << "Invalid. You entered a negative number." << endl;
else
cout << "You entered either 0 or an invalid number." << endl;
I get a really long error message when I try this. Starts off like this...really really long: error C2676: binary '/' : 'std::basic_string<_Elem,_Traits,_Ax>' does not define this operator or a conversion to a type acceptable to the predefined operator 1> with 1> [ 1> _Elem=char, 1> _Traits=std::char_traits<char>, 1> _Ax=std::allocator<char> 1> ] 1>c:\users\austin\documents\visual studio 2005\projects\scores\scores\scoresc.cpp(62) : error C2676: binary '/' : 'std::basic_string<_Elem,_Traits,_Ax>' does not define this operator or a conversion to a type acceptable to the predefined operator 1> with 1> [ 1> _Elem=char, 1> _Traits=std::char_traits<char>, 1> _Ax=std::allocator<char> 1> ] 1>c:\users\austin\documents\visual studio 2005\projects\scores\scores\scoresc.cpp(66) : error C2784: 'bool std::operator >=(const std::basic_string<_Elem,_Traits,_Alloc> &,const _Elem *)' : could not deduce template argument for 'const _Elem *' from 'int' 1> c:\program files\microsoft visual studio 8\vc\include\string(241) : see declaration of 'std::operator >=' 1>c:\users\austin\documents\visual studio 2005\projects\scores\scores\scoresc.cpp(66) : error C2784: 'bool std::operator >=(const _Elem *,const std::basic_string<_Elem,_Traits,_Alloc> &)' : could not deduce template argument for 'const _Elem *' from 'std::basic_string<_Elem,_Traits,_Ax>' 1> with 1> [ 1> _Elem=char, 1> _Traits=std::char_traits<char>, 1> _Ax=std::allocator<char>
atoi returns an integer. If you want a float or a double, you need to use something else.
int atoi ( const char * str );
atof returns a double, so that's better. it's basically the same as strtod, but strtod is considered "safer", I think. You can use either, but I think strtod is generally considered better.
double atof ( const char * str );
None of these functions takes a string as an argument. They take C-Strings (char*), so you need something to convert them, which is where the string::c_str function comes in (see link above):
const char* c_str ( ) const;
Ok so I would want
string test1;
const char* c_str (test1 ) const;
I really need someone to spell out an example similiar to what I'm doing, sorry this stuff just goes right over my head.
My program works fine and I was really proud, but this verifying input has got me down in the dumps.
Looks like you are dividing by 2, then multiplying by 2, which cancel each other out, so do you want to simplify it to this?
if
(test1 + test3 >= 90)
Hehe yeah I noticed that as well. I originally intended the program to take an average of the two numbers before I realized I only had test scores that were out of 50 points :).
I've been reading around on input verification and have only come across one way that may work. It created a 2 character array to enter the numbers and then converts the character to # and if that fails it prompts the users to enter only numbers.
Just wondering if that's the easiest way to approach this?
Wow thanks! I really wanted to create an "in between" variable to store the score, just didn't know what it was called. I will try this later today but it looks like it will solve a lot of my problems.
I am working on a little program here and need some help. The input is 3 test grades that are out of 50 points total, the program takes the higher of the first 2 test grades and adds that to the last test grade to determine a final score.
This is where I need my first bit of help, as you can see the code below isn't quite up to par. It will correctly give you a final grade, but it also gives 2 other grades in addition because of how I set up the if statements. I'm not sure where to add an else because I don't want it to say if you dont get an A then else you get BCDF or something. I was trying to use the && or || possibly but can't figure out how to get what I want.
Also I need help verifying the input the user enters, if they enter negative numbers or letters it crashes the program. Like something that prompts the user "no negative numbers, try again".
# include <string>
# include <iostream>
using namespace std;
int main()
{
string name;
float test1;
float test2;
float test3;
cout << "Welcome to the Grade Calculator Machine. You will enter three test scores." <<endl;
cout << "The higher of the first two test grades will be added with the third test grade" <<endl;
cout << "to determine the final grade average for the course." <<endl<<endl;
cout …
