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Closed 10 years ago.
Just making a small program to begin c++ and the compiler says that there is an else without an if in reference to the while loop in main, though it is clearly not the case and I cannot see why. It works fine if I remove the while loop.
#include <iostream>
using namespace std;
int number;
int arithmetic(int num)
{
if(num > 20)
num = num * 5;
else
num = 0;
return (num);
}
int main()
{
int wait;
cout << "I will take any number providing it is higher than twenty" << endl;
cout << "and I will multiply it by 5. I shall then print every number" << endl;
cout << "from that number backwards and say goodbye." << endl;
cout << "Now please give me your number: " << endl;
cin >> number;
int newnum = arithmetic(number);
if (newnum != 0)
cout << "Thank you for the number, your new number is" << newnum << endl;
while(newnum > 0){
cout << newnum;
--newnum;
}
cout << "bye";
else
cout << "The number you entered is not greater than twenty";
cin >> wait;
return 0;
}
You are missing brackets. You have
if (newnum != 0)
cout << "Thank you for the number, your new number is" << newnum << endl;
while(newnum > 0){
cout << newnum;
--newnum;
}
cout << "bye";
else
cout << "The number you entered is not greater than twenty";
while you should have:
if (newnum != 0)
{
cout << "Thank you for the number, your new number is" << newnum << endl;
while(newnum > 0){
cout << newnum;
--newnum;
cout << "bye";
}
else
cout << "The number you entered is not greater than twenty";
If you have more than one operation in if statement, you should always use brackets. If you have just one, you can as well omit them (as in this "else" statement).
You need a { after if (newnum != 0) and a } before the else.
This type of construction is wrong:
if(something)
line1;
line2; // this ; disconnects the if from the else
else
// code
You need something like
if ( something ) {
// more than one line of code
} else {
// more than one line of code
}
Related
#include <iostream>
#include <vector>
using namespace std;
string disease(vector<string> symptom, vector<string> name, int patientnum){
string holder;
cout << "is " << name[patientnum] << " experiencing " << symptom[patientnum] << " Y/N";
cin >> holder;
if(holder == "Y" || holder == "y"){
return symptom.push_back("Y");
}
else if(holder == "N" || holder == "n"){
return symptom.push_back("N");
}
else{
cout <<"Please input Y/N" << endl;
cout <<"Program exiting...";
}
}
int main()
{
vector<string> dry, sneeze, namex;
int patientn = 0;
string input;
while(patientn < 2){
cout << "Name: ";
cin >> input;
namex.push_back(input);
disease(dry[patientn], namex[patientn], patientn);
patientn++;
}
for(patientn=0; patientn<namex.size(); patientn++){
cout << namex[patientn] << " is experiencing dry cough = " << dry[patientn] << endl;
cout << namex[patientn] << " is experiencing sneezing = " << sneeze[patientn] << endl;
}
return 0;
}
This is the error im getting
error: could not convert ‘symptom.std::vector<_Tp, _Alloc>::push_back, std::allocator > >(std::basic_string(((const char*)"Y"), std::allocator()))’ from ‘void’ to ‘std::string {aka std::basic_string}’
Im a freshmen in IT, so im sorry if my logic for making this program is stupid, and my variables naming are confusing.
So in the while loop im asking for a name and then storing it inside a name vector and then i call the function to ask for an input. "
cout <<"Is " << name << " experiecing " << symptom; //something like this but i also use an int patientnum to get the name[patientnum]
and then get y/n as the answer.
Then i make an if that accepts uppercase or lowercase answer and return symptom.push_back "Y" or "N"
and the for loop on the bottom is to print the name and then Y/N
Or can you guys suggest me a better way of doing this, im willing to learn anything.
Change the function to void, since you don't want to return anything from it.
void disease(vector<string> symptom, vector<string> name, int patientnum){
string holder;
cout << "is " << name[patientnum] << " experiencing " << symptom[patientnum] << " Y/N";
cin >> holder;
if(holder == "Y" || holder == "y"){
symptom.push_back("Y");
}
else if(holder == "N" || holder == "n"){
symptom.push_back("N");
}
else{
cout <<"Please input Y/N" << endl;
cout <<"Program exiting...";
}
}
Unfortunately that's only one of many issues with your code.
Incidentally if you spend some time choosing logical and meaningful names for your functions and variables you will find the programming easier. Funny that. Half the battle with programming is thinking clearly about what you are doing, and meaningless or arbitrary names show that you aren't thinking clearly.
I am creating a guessing game. I need to ask the user to input a letter from a word like fallout. The have that letter they had inputted be correct or incorrect. I am using functions like srand(time(NULL)), rand(), psw.length. once the user inputs a letter and if they are wrong a life is deducted live--.
If they get it right they can move on to the next question with a full 5 lives. I don't know what functions I am missing if I need an array etc.
I have tried applying the rand() && psw.length together in order to at least try to randomize the letter choice so that the user might have a chance to guess the random letter from the word "fallout" but to no avail.
I have made some progress I started with the numerical portion of the code instead of focusing on the whole thing at once. Then now I have to start on the alphabetical portion of the code itself I am organizing my thoughts to simpler terms.
Now onto the alphabetical functions of the code....I now need to randomize letters for the user to answer with the correct letter of the word using functions.
I am trying to make the second answer2 = rand() % word2.length function work could anyone help me here it automatically runs the code giving a positive score to the user....
include <iostream>
#include <string>
#include <time.h>
#include <cstdlib>
using namespace std;
int lives = 3;
int guess;
int guess2;
int answer = 0;
int answer2 = 0;
int i;
int score = 0;
char letter, letter2;
string word = "fallout";
string word2 = "psw";
int main()
{
srand(time(NULL));
cout << "Welcome to the guessing game!" << endl;
cout << "*****************************" << endl;
system("PAUSE");
system("cls");
answer = rand() % 2 + 1;
lives = 3;
do {
cout << "What is a number between 1 and 2? Can you guess it in\n" << endl << lives << endl << "tries?" << endl;
cin >> guess;
if (guess == answer)
{
cout << "You won!!" << endl;
score++;
}
else if (lives == 0)
{
cout << "Your score" << endl << score;
system("PAUSE");
return 0;
}
else
{
cout << "Incorrect try again!" << endl;
lives--;
system("PAUSE");
system("cls");
}
} while (guess != answer);
cout << "You won your score is" << score << endl;
system("PAUSE");
system("cls");
answer = rand() % 3 + 1;
lives = 3;
do {
cout << "What is a number between 1 and 3? Can you guess it in" << endl << lives << "tries?" << endl;
cin >> guess;
if (guess == answer)
{
cout << "You won!!" << endl;
score++;
}
else if (lives == 0)
{
cout << "Your score" << endl << score;
system("PAUSE");
return 0;
}
else
{
cout << "Incorrect try again!" << endl;
lives--;
system("Pause");
system("cls");
}
} while (guess != answer);
cout << "You won your score is" << score << endl;
system("PAUSE");
system("cls");
answer = rand() % 5 + 1;
lives = 3;
do {
cout << "What is a number between 1 and 5? Can you guess it in\n" << endl << lives << "tries?" << endl;
cin >> guess;
if (guess == answer)
{
cout << "You won!!" << endl;
score++;
}
else if (lives == 0)
{
cout << "Your score" << endl << score;
system("PAUSE");
return 0;
}
else
{
cout << "Incorrect try again!" << endl;
lives--;
system("cls");
}
} while (guess != answer);
cout << "You won your score is " << score << endl;
system("PAUSE");
system("cls");
answer = rand() % word.length();
lives = 3;
do
{
cout << "Select the correct letter in the word '" << word << "': ";
cin >> guess;
if (guess == letter)
{
cout << "You Won!" << endl;
score++;
}
else if (lives == 0)
{
cout << "The correct answer is:" << endl;
cout << word[answer];
}
else
{
cout << "Incorrect Try Again" <<
lives--;
}
} while (guess != letter);
cout << "You won your score is " << score << endl;
system("PAUSE");
system("cls");
How can I make this code run well can anybody help me I just need advice on this function here... It keep giving the user a score++ automatically. Is their a simple fix for this. I am a rookie so if there is a basic trick here it would help!
answer2 = rand() % word2.length();
lives = 3;
do
{
cout << "Select the correct letter in the word '" << word2 << "': ";
cin >> guess2;
if (guess2 == letter2)
{
cout << "You Won!" << endl;
score++;
}
else if (lives == 0)
{
cout << "The correct answer is:" << endl;
cout << word2[answer2];
}
else
{
cout << "Incorrect Try Again" <<
lives--;
}
} while (guess2 != letter2);
cout << "You won your score is " << score << endl;
system("PAUSE");
system("CLS");
}
First of all, in C++ you have some different ways to randomize a value. rand() highly not recommended.
From cppreference:
There are no guarantees as to the quality of the random sequence produced. In the past, some implementations of rand() have had serious shortcomings in the randomness, distribution and period of the sequence produced (in one well-known example, the low-order bit simply alternated between 1 and 0 between calls). rand() is not recommended for serious random-number generation needs, like cryptography.
Instead, you can use:
#include <random>
int main() {
/*...*/
// Seed with a real random value, if available
std::random_device r;
// Choose a random mean between 1 and 6
std::default_random_engine e1(r());
std::uniform_int_distribution<int> uniform_dist(1, 7);
answer = uniform_dist(e1);
/*...*/
return 0;
}
Read more about random: https://en.cppreference.com/w/cpp/numeric/random
For loop - Condition problem: for (int i = 0; i < guess; i++) - The condition here seems wrong. Why does this loop runs until i is bigger then the user guess? I think a better way for your target is to use while loop, until the user have no lives:
int lives = 5;
size_t guess_number = 1;
/*...*/
while (lives) {
cout << "Guess" << guess_number++ << endl;
/*...*/
}
Stop the loop: Whenever the user successfully guess the letter (or the letter's place in the word), you might considering random a new letter, a new word, or just stop the game and exit the loop (with break).
The word FALLOUT: Currently, in your code, the word fallout ia a variable name, and not a variable content. start with replacing this name to something like word_to_guess, and put the value fallout into it.
string fallout;
to:
string word_to_guess = "fallout";
Now that you have done it, you can make you code more generic to another words, by choosing a random number between 1 to word_to_guess.size():
std::uniform_int_distribution<int> uniform_dist(1, word_to_guess.size());
Now you want to convert user's guess and computer's guess to letters:
/**
* guess >= 1 - The user have to guess a letter from the beginning of the word (and not before it).
* guess <= word_to_guess.size() - The user can't guess a letter that not exists in the word.
* word_to_guess[guess - 1] == word_to_guess[answer - 1] - Compare the user's letter to the computer's letter
*
* word_to_guess[answer - 1] - You might consider to replace this with word_to_guess[answer], and just random
* a number from 0 to word_to_guess.size() - 1
*/
if (guess >= 1 && guess <= word_to_guess.size() && word_to_guess[guess - 1] == word_to_guess[answer - 1]) {
cout << "You Won" << endl;
break; // Or random new letter/word etc...
}
Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 6 years ago.
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I am new to programming and I need help with my term project. I have made a program that simulates a hotel booking, the problem is that whenever a non-whole number is entered for the first question, it goes into an infinite loop. If you get to the second question and enter a non-whole number it accepts it as a whole number by dropping off anything that comes after the decimal and then skips the next question and stops running the program.
#include <iostream>
#include <string>
using namespace std;
int stay_length (int stay)
{
int nights = stay;
int total = 0*nights;
return total;
}
int rooms_booking(int rooms)
{
int rooms_booked = rooms;
int total = 0;
if(rooms_booked > 0)
{
total = rooms_booked * 50;
}
else
{
total = 0;
}
return total;
}
int main(){
int x;
string repeat;
int nights;
int total = 0;
int rooms_avail = 10;
int rooms;
cout << "Hello! Welcome to Hotel COMP 150." << endl;
do {
if (rooms_avail > 0) {
cout << "How many nights will you be staying?" << endl;
}
else {
cout << "Sorry, but there are no rooms available. " << endl;
}
do {
cin >> nights;
if (nights > 0 && nights <= 28)
{
int total1 = stay_length(nights);
cout << "You are staying for " << nights << " nights" << endl;
cout << "That costs: $" << total1 << endl;
total = total + total1;
}
else
{
cout << "You cannot stay less than 1 or more than 28 nights" << endl;
}
} while (nights <= 0 || nights >28);
if (rooms_avail > 0)
{
cout << "How many rooms will you be booking?" << endl;
cout << "There are " << rooms_avail << " available." << endl;
cin >> rooms;
if (rooms > 0 && rooms <= rooms_avail)
{
int total2 = rooms_booking(rooms);
cout << "You are booking " << rooms << " rooms." << endl;
cout << "That costs : $" << total2 << endl;
total = total + total2;
rooms_avail = rooms_avail - rooms;
}
else if (rooms <= 0 || rooms > rooms_avail)
{
do{
cout << "You can only book a minimum of 1 room or a maximum of " << rooms_avail << endl;
cin >> rooms;
} while (rooms <= 0 || rooms > rooms_avail );
int total2 = rooms_booking(rooms);
cout << "You are booking " << rooms << " rooms." << endl;
cout << "That costs : $" << total2 << endl;
total = total + total2;
rooms_avail = rooms_avail - rooms;
}
else
{
cout << "You cannot book more than " << rooms_avail << endl;
}
}
else
{
cout << "Sorry, all rooms have been booked." << endl;
}
cout << "Your total so far is: $" << total << endl;
cout << "Would you like to make another booking? Enter 'Y' or 'y' to do so." << endl;
cin >> repeat;
}while(repeat == "Y" || repeat == "y");
return 0;
}
It's always better to use std::getline() instead of operator>> to read interactive input from std::cin.
operator>> is not for reading a single line of text from standard input, and storing it. That's what std::getline() is for.
If the wrong kind of input is entered, not what operator>> expects, it sets std::cin to a failed state, which makes all future attempts to read std::cin immediately fail, resulting in the infinite loop you are observing.
To do this correctly, it is going to be either:
1) Always check fail() after every operator>>, to see if the input failed, if so recover from the error with clear(), then ignore(). This gets real old, very quickly.
2) It's much easier to read a single line of text with std::getline(), then parse the input yourself. Construct a std::istringstream, if you wish, and use operator>> with that, if that makes it easier for you.
You can achieve basic user-input error checking via the console with something along these lines:
int nights = 0;
// error checking loop
while(1) {
std::cout << "How many nights will you be staying?" << endl;
std::cin >> nights;
// input valid
if(!std::cin.fail() && (std::cin.peek() == EOF || std::cin.peek() == '\n')
&& nights > 0 && nights <= 28) {
// do stuff
break; // break from while loop
}
// input invalid
else {
std::cin.clear();
std::cin.ignore(256, '\n');
std::cout << "An input error occurred." << std::endl;
}
}
I'm studying at university and we started programming in C++. I had some basic concepts about Java (variables, loops and more easy things) and I tried to practice on my own with Microsoft Visual Studio, but I had a problem, this is my code, is a program that tries to guess the number you are thinking of.
void main(){
srand(time(NULL));
int number=1+rand()%100;
int highLow;
bool a;
a = true;
cout << "Think a number between 1 and 100 and I will guess it" << endl;
system("PAUSE");
cout << "\nIs it ";
cout << number;
cout << "?" << endl;
cout << "If the number is lower press 1, higher 2 and correct 3" << endl;
cin >> highLow;
while (a)
{
if (highLow == 1)
{
number = 1 + rand() % number;
cout << "\nIs it ";
cout << number;
cout << "?" << endl;
cin >> highLow;
}
else if (highLow == 2)
{
number = rand() % (100 - number+1)+number;
cout << "\nIs it ";
cout << number;
cout << "?" << endl;
cin >> highLow;
}
else if (highLow == 3)
cout << "I win this time" << endl;
a = false;}
}
The problem is that it should ask the user as many times as needed to guess the number, but it only does 2 times, then stops. Can you help me please?
If only you had indented your code properly…
The last a = false; statement executes no matter what, because it's outside the scope of the last else if statement. Basically, this:
else if (highLow == 3)
cout << "I win this time" << endl;
a = false;
means the following:
else if (highLow == 3) {
cout << "I win this time" << endl;
}
a = false;
You need to add some curly braces where appropriate.
I am doing a quiz and testing the user. If the user is wrong he is allowed a second chance or skip, if he chooses 2nd chance and is wrong again, the game is over. How do I break out of this loop to end the game? I tried a do while loop,
do { stuff} while (wrong<2) while counting ++wrong;
every time he's wrong, but didnt work.
I have labeled the ++wrong with // statements below
void player_try (string questions[][5], char answers[])
{
char user_guess;
int m = 0;
srand(time(NULL));
int x;
int choice;
int wrong =0;
for (m=0; m<7; m++)
{
do
{
x = (rand() % 7);
cout << user_name << ": Here is question number " << m+1 << endl;
cout << m+1 << ". " << questions[x][0]<< endl;
cout << "A. " << questions[x][1]<< endl;
cout << "B. " << questions[x][2]<< endl;
cout << "C. " << questions[x][3]<< endl;
cout << "D. " << questions[x][4]<< endl;
cin >> user_guess;
user_guess = toupper(user_guess);
while (!(user_guess >= 'A' && user_guess <= 'D'))
{
cout << "Please choose a valid answer.";
cin>> user_guess;
}
if (user_guess != answers[x])
{
cout <<"Wrong!" <<endl;
++wrong; // THIS IS WHERE I COUNT WRONG ONCE
cout << "Skip this question or take a chance at greatness?" << endl;
cout << "Press 1 to skip, press 2 to take a chance at greatness" << endl;
cin >> choice;
if (choice == '1')
{
cout << "we shall skip this question." << endl;
}
else
{
cout << "I applaud your bravery." << endl;
cout << user_name << ": Here is question number " << m+1 << endl;
cout << m+1 << ". " << questions[x][0]<< endl;
cout << "A. " << questions[x][1]<< endl;
cout << "B. " << questions[x][2]<< endl;
cout << "C. " << questions[x][3]<< endl;
cout << "D. " << questions[x][4]<< endl;
cin >> user_guess;
user_guess = toupper(user_guess);
while (!(user_guess >= 'A' && user_guess <= 'D'))
{
cout << "Please choose a valid answer.";
cin>> user_guess;
}
}
if (toupper(user_guess) != answers[x])
{
cout <<"Wrong!" <<endl;
++wrong;; // THIS IS WHERE I CANT WRONG TWICE
}
else
{
cout << "correct!" << endl;
}
}
else
{
cout << "correct!" << endl;
}
}
while(wrong < 2);
}
}
Change your function return type to an integer. That simply means changing "void" to "int."
Then, inside the function place a return 0; at the point you want your function to terminate. Be sure you include another return 1; for the case that the user wins too.
This is how the main() function works. Consider:
int main()
{
string tester = "some string";
if(tester == "some string")
return 1;
cout << "Hey!"
return 0;
}
In the above case, main() terminates at the "return 1;" because the if statement was TRUE. Note that "Hey!" is never printed. It'll work the same way for your function.
As a plus, you can use that return value to let OTHER functions (such as main()) know if the function terminated because the user won (it returned 1), or lost (it returned 0).
Yes, a break statement is also a valid way to terminate the loop, but I submit that this method is the safer, cleaner way to go about it. In general, we like to know whether a function or program was successful or not.
You can use a break; statement if the person has gotten the answer wrong twice.
As per comments. You can shed the do while loop in favour of one for loop. Just put a break at the bottom if the wrong guesses are 2
There are several great suggestions for refactoring the code to remove the duplication of effort here, but to get the program functioning immediately, you've got to break out of the for loop surrounding the do { } while(wrong < 2) loop.
A simple way to do this is to modify the for loop to test the wrong variable also. The added benefit is, if I'm reading everything correctly, you'll no longer need the do{ } while(); loop.
for (m=0; m<7 && wrong < 2; m++)