The only way the loop works is when the player runs out of lifes. The game is supposed to allow the player to answer math questions, they answer until either they, or the magician runs out of lives. So int the do while loop, the while is only working once pLife runs out, and completely ignores eLife, why is that?
do
{
int Number = rand() % 20 + 1; //Desides the random number that will be used in the program
int aNumber = rand() % 20 + 1;
int rng = rand() % 3 + 1;
cout <<"Player Life Total = " <<pLife <<endl;
cout <<"Mathmagican Life Total = " <<eLife <<endl;
if (rng == 1)
{
cout <<"What is " <<Number <<"X" << aNumber <<"?\n\n";
cin >> answer;
if (answer == Number * aNumber)
{
cout <<"What!!! How is that possible you deflected my attack!\n\n";
cout <<"Ahh it hit me!! you hit me with my own magic! Thats not fair!\n\n";
eLife = eLife- 1;
}
else if (answer > Number * aNumber, answer < Number * aNumber)
{
cout <<"I told you that you couldn't defeat me!\n\n";
cout <<"Now die!";
pLife = pLife - 1;
}
}
else if (rng == 2)
{
cout <<"What is " <<Number <<"-" << aNumber <<"?\n\n";
cin >> answer;
if (answer == Number - aNumber)
{
cout <<"What!!! How is that possible you deflected my attack!\n\n";
cout <<"Ahh it hit me!! you hit me with my own magic! Thats not fair!\n\n";
eLife = eLife- 1;
}
else if (answer > Number - aNumber, answer < Number - aNumber)
{
cout <<"I told you that you couldn't defeat me!\n\n";
cout <<"Now die!";
pLife = pLife - 1;
}
}
else if (rng == 3)
{
cout <<"What is " <<Number <<"+" << aNumber <<"?\n\n";
cin >> answer;
if (answer == Number + aNumber)
{
cout <<"What!!! How is that possible you deflected my attack!\n\n";
cout <<"Ahh it hit me!! you hit me with my own magic! Thats not fair!\n\n";
eLife = eLife- 1;
}
else if (answer > Number + aNumber, answer < Number + aNumber)
{
cout <<"I told you that you couldn't defeat me!\n\n";
cout <<"Now die!";
pLife = pLife - 1;
}
}
}while (eLife > 0, pLife > 0);
if (eLife == 0)
{
cout <<"Oh no! I cant belive it... you... actualy... defeated me?!\n\n";
cout <<"NO!!! CURSE YOU!!!";
cout <<"You've Won!\n\n";
system ("pause");
return 0;
}
else if (pLife == 0)
{
cout <<"MWAHAHAHAHAHA!!!!! I told you i would win!\n\n";
cout <<"Game over";
system ("pause");
return 0;
}
}
Each of the individual expressions in comma-separated expressions will be evaluated and their side effects will take place. However, the value of an entire comma-separated expression is only the result of the rightmost expression. Thus, the while condition evaluates as true only if pLife > 0 returns true.
To correct the problem, change it to a single expression using boolean operators such as && or ||
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I am writing a program to calculate the grade of 3 test scores. The lowest of the first 2 scores is dropped and added to the third test score to make the final grade. The 3 test scores cannot be higer than 50, lower than 0 and cannot be a character or string. So far, I have satisified all those requirment but I need to implement decimal grades to the program like for instance 45.5. Also to round the final grade up or down. For example if final grade is 89.5 round up to an A.
#include <iostream>
#include <algorithm>
#include <cstdlib>
using namespace std;
char getGrade(int num) {
if (num < 60)
return 'F';
if (num < 69)
return 'D';
if (num < 79)
return 'C';
if (num < 89)
return 'B';
return 'A';
}
bool isnumeric(string temp) {
for (char &chr : temp) {
if ((chr >= '0' and chr <= '9') or chr == '-')
continue;
else
return false;
}
return true;
}
int main(int argc, char const *argv[]) {
cout << "Welcome to the grade calculator.You will input three test "
"scores.\nThe highest of the first two grades and the third grade "
"will be\nadded together to determine the numeric grade average for "
"the\ncourse.Each test score has a maximum of 50 points.\n";
int arr[3];
int ctr = 0;
string temp;
int num;
while (ctr < 3) {
cout << "\nPlease enter test score " << (ctr + 1) << ": ";
label1:
cin >> temp;
if (isnumeric(temp)) {
num = atoi(temp.c_str());
if (num > 50) {
cout << "\nTest scores cannot be higher than 50, try again: ";
goto label1;
} else if (num < 0) {
cout << "\nTest scores cannot be negative, try again: ";
goto label1;
} else {
arr[ctr++] = num;
}
} else {
cout << "\nInvalid test score entered, try again: ";
goto label1;
}
}
int average = 0;
average = max(arr[0], arr[1]);
average = average + arr[2];
cout << "\nThe average for the course = " << average << "\n";
cout << "The letter grade = " << getGrade(average);
cout << "\n\n\nThank you for using this program\n";
return 0;
}
Just changed a couple of things to make it work with decimals:
1. Added chr == '.' to the isNumeric() function:
bool isnumeric(string temp) {
for (char& chr : temp) {
if ((chr >= '0' and chr <= '9') or chr == '-' or chr == '.')
continue;
else return false;
}
return true;
}
2. Changed variable types:
double arr[3]{};
int ctr = 0;
std::string temp;
double num;
3. Removed goto: (You can just use continue)
while (ctr < 3) {
std::cout << "\nPlease enter test score " << (ctr + 1) << ": ";
std::cin >> temp;
if (isnumeric(temp)) {
num = atof(temp.c_str());
if (num > 50) {
std::cout << "\nTest scores cannot be higher than 50, try again: ";
continue;
}
else if (num < 0) {
std::cout << "\nTest scores cannot be negative, try again: ";
continue;
}
else {
arr[ctr++] = num;
}
}
else {
std::cout << "\nInvalid test score entered, try again: ";
continue;
}
}
4. For rounding off, you can use std::round() as such:
double average = 0;
average = std::max(arr[0], arr[1]);
average = std::round(average + arr[2]);
You can also change your cout statements:
std::cout << "\nThe average for the course = " << average;
if (std::round(average) != average) std::cout << ", rounded off to = " << std::round(average);
std::cout << ".\nThe letter grade = " << getGrade(average);
std::cout << "\n\n\nThank you for using this program\n";
Just make all these changes and your program will successfully work with decimals.
Also, consider not using the following in your code:
using namespace std;
..as it's considered as a bad practice. For more info on why, look up to Why is using namespace std considered as a bad practice.
Edit: To accomplish your requirement, you can just change the while loop as such:
while (ctr < 3) {
if (temp.size() == 0)
{
std::cout << "\nPlease enter test score " << (ctr + 1) << ": ";
std::cin >> temp;
}
if (isnumeric(temp)) {
num = atof(temp.c_str());
if (num > 50) {
std::cout << "\nTest scores cannot be higher than 50, try again: ";
std::cin >> temp;
continue;
}
else if (num < 0) {
std::cout << "\nTest scores cannot be negative, try again: ";
std::cin >> temp;
continue;
}
else {
arr[ctr++] = num;
temp.clear();
}
}
else {
std::cout << "\nInvalid test score entered, try again: ";
std::cin >> temp;
continue;
}
}
The above code works as you said.
I found an RPS game and wanted to improve on it by creating a scoring system but the //int compwin = compwin + 1; keeps giving me errors. I am still fairly new to coding in C++ and have no clue where the problem is standing so thanks for helping in advance. Also this code was taken from somewhere this is not my code but I wanted to try and improve on it.
#include <iostream>
#include <cstdlib>
#include <limits>
#include <ctime>
#include <string>
using namespace std;
int main()
{
int choice;
int i;
int y;
int Y;
int comp;
char res;
int compwin = 0;
int choicewin = 0;
unsigned seed;
while (1==1) {
//The choices
cout << "Game Choices.\n\n";
cout << "1.Rock\n";
cout << "2.Paper\n";
cout << "3.Scissors\n";
cout << "4.Quit, exits the game.\n\n";
cout << "Please enter your choice.\n\n";
cin >> choice;
//-----------------------Player Imputs-----------------------------------
if (choice == 1) //Rock
{
cout << "You picked Rock.\n";
cout << "Now here was my choice.\n\n";
}
else if (choice == 2) //Paper
{
cout << "You picked Paper.\n";
cout << "Now here was my choice.\n\n";
}
else if (choice == 3) //Scissors
{
cout << "You picked Scissors.\n";
cout << "Now here was my choice.\n\n";
}
else if (choice == 4)
{
return 0;
}
else if (choice != 1 || 2 || 3 || 4) // Debug
{
cout << "Uhhhh thats not one of the following.\n\nGoodbye!\n\n";
system("pause");
return 0;
}
//-------------------------Computer Choice-------------------------------
seed = time(0);
srand(seed); //RNG TIME
comp = rand() % 3 + 1; //Computer picks
if (comp == 1) //Computer rock
{
res = 1;
cout << "Rock!\n\n";
}
else if (comp == 2) //Computer paper
{
res = 2;
cout << "Paper!\n\n";
}
else if (comp == 3) // Computer scissors
{
res = 3;
cout << "Scissors!\n\n";
}
//-----------------------Victory Conditions------------------------------
if (comp == 1 && choice == 1) {
std::cout << "It was a tie!" << endl;
}
else if (comp == 1 && choice == 3) {
std::cout << "I Won! Better luck next time!" << endl;
//int compwin = compwin + 1; This is where the problem occurs
}
else if (comp == 2 && choice == 2) {
std::cout << "It was a tie!" << endl;
}
else if (comp == 2 && choice == 1) {
std::cout << "I Won! Better luck next time!" << endl;
//int compwin = compwin + 1; This is where the problem occurs
}
else if (comp == 2 && choice == 3) {
std::cout << "It was a tie!" << endl;
}
else if (comp == 2 && choice == 2) {
std::cout << "I Won! Better luck next time!" << endl;
//int compwin = compwin + 1; This is where the problem occurs
}
else {
std::cout << "Congrats! You won!" << endl;
//int choicewin = choicewin + 1; This is where the problem occurs
}
cout << "Heres the score, computer =" << compwin << "and player =" << choicewin;
cout << "Want to go again? (y/n)";
cin >> res;
system("cls");
}
while (res == y || Y);
system("pause");
return 0;
}
This
int compwin = compwin + 1;
is a declaration and initialization. A rather weird one, and to discuss why it is allowed would take us on a too big detour. So lets look at a simpler example:
int compwin = 1; // declares compwin and initializes it with 1
int compwin = 2; // compiler error, because compwin is already declared
You can only declare the same variable once (again the long complete truth is more involved, search for "shadowing" in case you care). You also only need to initialize a variable only once.
If you want to assign something to an already declared variable, you use assignment, as in
int compwin = 1; // declare and initialize
compwin = 2; // assign
Further note that
else if (choice != 1 || 2 || 3 || 4) // Debug
is not doing what you expect. The correct way is
else if (choice != 1 && choice != 2 && choice != 3 && choice != 4)
The mistake is a combination of ignoring De Morgan's Law and a wrong combination of several conditions. The operator|| expects a bool on both sides and unfortunately numbers happily convert to true (only 0 becomes false), but a good compiler may spit out warnings on that. Similar mistake is on while (res == y || Y);.
int main() {
power=1;
while (1 == 1){
tapcost=power*3;
cout << "type upgrade/buy/a" << endl;
cin >> way;
if (way == "upgrade"){
cout << "1. A Power " << "(Costs: " << tapcost << ")" << endl;
cin >> upgr;
if (upgr == 1){
if (0<=money-power*3){
power=power+1;
money=money-power*3;
}
else
cout << "You can't afford that!!!" << endl;
}
}
if (way == "a"){
money=money+power;
}
}
return 0;
}
When I type upgrade and then type anything else other than the variable "1", the code will repeat infinitely.
This is a never-ending problem.
See this question: Infinite loop with cin when typing string while a number is expected
I think your code have some mistakes.
int upgr;
cin >> upgr; // you can type any number you want (-2 147 483 648 / 2 147 483 647)
I suggest you to use getline, cin.getline or fgets instead of cin >> when reading a line.
And just use while(1) or while(true)
You have created an infinite loop by never changing the value of your ‘1’ variable. In some way you need to change that value when iterating through your conditions or else you’ll never get out of your loop.
You could also try out something like that.
char i;
while((std::cin >> i) && i != '1') {
....
}
In your code, while (1 == 1) creates an infinite loop. Since I assume you want this code to keep asking players for their input until they decide to stop, you can add an option exit which breaks out of the loop when the player wants to.
#include <iostream>
int main() {
int power = 1;
int money = 1000;
while (1 == 1) {
int tapcost = power * 3;
std::string way;
std::cout << "type upgrade/buy/a/exit" << std::endl;
std::cin >> way;
if (way == "upgrade") {
std::cout << "1. A Power " << "(Costs: " << tapcost << ")" << std::endl;
int upgr;
std::cin >> upgr;
if (upgr == 1) {
if (0 <= money - power * 3) {
power = power + 1;
money = money - power * 3;
}
else {
std::cout << "You can't afford that!!!" << std::endl;
}
}
}
if (way == "a") {
money = money + power;
}
if (way == "exit") {
break;
}
}
return 0;
}
I'm trying to get the program to loop again, up to three times, if the user entered a number that does not follow the function defined in the if statement. The code as is, only loops once and then exits. Did I type the for loop incorrectly or is it the if...else statement that is wrong?
#include <iostream>
using std::cout; using std::cin; using std::endl;
int main() {
cout << "Enter a positive odd number less than 40: ";
int num = 0;
for (int a = 0; a < 3; ++a);
cin >> num;
{
if (num < 40 && num > 0 && num % 2 == 1)
{
cout << "Thank you!" << endl;
}
else cout << "That is incorrect, try again!" << endl;
}
}
Did I type the for loop incorrectly or is it the if...else statement that is wrong?
Both. You should (1) remove the semicolon following the for statment; (2) move cin >> num into the for loop body; (3) add break; inside the if.
for (int a = 0; a < 3; ++a)
{
cin >> num;
if (num < 40 && num > 0 && num % 2 == 1)
{
cout << "Thank you!" << endl;
break;
}
else cout << "That is incorrect, try again!" << endl;
}
BTW1: Try to use the debugger, then you'll find out what happened in fact.
BTW2: The code will fail when cin >> num fails (e.g. user entered an invalid value), you might need to check the result of cin >> num, to process the case. Such as:
for (int a = 0; a < 3; ++a)
{
if (cin >> num)
{
if (num < 40 && num > 0 && num % 2 == 1)
{
cout << "Thank you!" << endl;
break;
}
else cout << "That is incorrect, try again!" << endl;
}
else
{
cin.clear(); // unset failbit
cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // skip bad input
cout << "Wrong input, try again!" << endl;
}
}
bool isValid = false;
int num;
while(!isValid)
{
cout << "enter a positive odd integer " << endl;
cin >> num;
if(num < 40 && num > 0 && num % 2 == 1 )
{
cout << "thank you"<<endl;
isValid = true;
}
else
isValid = false;
}
Why not use some thing like this, it will loop until isValid = true which will only happen when your conditions are met?
I understand I guess, if you're doing a school project or some thing and you're forced to do it with a for loop but in general this would be a much better solution for some thing like this than a for loop!
I got an assignment where we make a cmd prompt show up and display a flashcard game for multiplication. After inputting a correct answer a prompt shows up and asks the user to go "Again? Y/N." after the second input answer the prompt to ask the user doesn't show up and it's stuck on a "congratulations" message. This happens when I write in code to randomly generate two numbers for the game twice. one outside the while loop, and one inside while loop. If I leave one out the 2nd code for the random numbers it will run fine but will only display the same numbers over again. what I'm asking is how do I fix it so that it won't get stuck after the second answer input?
sample code below:
#include <iostream>
using namespace std;
int main()
{
int num1, num2, ans, guess, count = 0;
char choice;
num1 = rand() % 12 + 1;
num2 = rand() % 12 + 1;
//first number generator.
ans = num1 * num2;
do
{
{
cout << num1 << " X " << num2 << " = ";
cin >> guess;
cout << "Wow~! Congratulations~! ";
count++;
num1 = rand() % 12 + 1;
num2 = rand() % 12 + 1;
//second number generator.
} while (guess != ans);
cout << "\nAgain? Y/N: ";
cin >> choice;
} while ((choice == 'y') || (choice == 'Y'));
//after two turns the loop stops. Can't make a choice.
cout << " Thanks for playing! Number of tries:" << count << endl;
return 0;
}
I'd guess the problem is because your loops aren't quite what you think they are.
do
{
The code above has started a do loop.
{
I suspect you intended to start another (nested) do loop here--but you left off the do, so it's just a block that gets entered, executed, and exited. Useless and pointless in this case.
cout << num1 << " X " << num2 << " = ";
cin >> guess;
cout << "Wow~! Congratulations~! ";
count++;
num1 = rand() % 12 + 1;
num2 = rand() % 12 + 1;
//second number generator.
} while (guess != ans);
You've formatted this as if the while were closing the nested do loop--but since you didn't actually create a nested do loop, this is just a while loop with an empty body. Its meaning would be more apparent with a little re-formatting:
// second number generator
}
while (guess != ans)
/* do nothing */
;
The problem can be found here:
do
{
{
cout << num1 << " X " << num2 << " = ";
cin >> guess;
As you can see, the second scope has no do statement. As a result it is only a codeblock.
You can solve it by writing a do statement for the second code block.
Because the do is not present in the second bracket ({), the while is interpreted as a while loop:
while (guess != ans);
or
while (guess != ans) {
}
this thus keeps looping until guess is not equal to ans. But since in the loop does not modify any of the two variables, the loop will keep iterating.
Other errors: note that the program is still incorrect, since it will claim you have answered the question, regardless of the answer. You can fix it by implementing this as follows:
int main()
{
int num1, num2, ans, guess, count = 0;
char choice;
do {
num1 = rand() % 12 + 1;
num2 = rand() % 12 + 1;
ans = num1 * num2;
do {
cout << num1 << " X " << num2 << " = ";
cin >> guess;
if(guess == ans) {
cout << "Wow~! Congratulations~! ";
} else {
cout << "No, wrong!\n";
}
count++;
} while (guess != ans);
cout << "\nAgain? Y/N: ";
cin >> choice;
} while ((choice == 'y') || (choice == 'Y'));
//after two turns the loop stops. Can't make a choice.
cout << " Thanks for playing! Number of tries:" << count << endl;
return 0;
}