C++ :: What Is The Type Specifier For Boolean

Dec 11, 2012

In the following example, how 'd I use sprintf when I have a boolean type of variable?

Code:
char s[64];
bool bVar = false;
sprintf(s, "This is a boolean variable bVar = %?", bVar);

What is supposed to replace ? in the sprintf statement ?

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C/C++ :: Read A Type Specifier From A File

Oct 28, 2014

I need to create certain objects which are listed in a file. So my code needs to run a loop and create objects(of type specified in file) and put them in a list.

It appears to me that type specifiers can't be replaced by string. Is there a way out ? I want following code to be working somehow.

#include <iostream>
#include <string>
using namespace std;

[Code].....

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C++ :: Access Serial Port - This Declaration Has No Storage Class Or Type Specifier

Feb 26, 2013

I am writing a code using Visual C++ to access serial port.

Code:
HANDLE hSerial= CreateFile(L"COM1", GENERIC_READ | GENERIC_WRITE,0,0,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
DCB dcb = {0};
dcb.DCBlength=sizeof(dcbSerialParams);
dcb.BaudRate=CBR_1200;
dcb.ByteSize=8;
dcb.StopBits=ONESTOPBIT;
dcb.Parity=NOPARITY;

I am getting error in all last five lines in above code at dcb. and error is give below:-

Error: this declaration has no storage class or type specifier

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C :: Width Specifier Does Not Align Like In Printf

Apr 19, 2013

I am currently debugging this function. I am trying to make this function's width specifier align like a printf() routine. Here 's the code:

v Code:
oid
bu_log(const char *fmt, ...) {
va_list ap;
struct bu_vls output = BU_VLS_INIT_ZERO;

if (UNLIKELY(!fmt || strlen(fmt) == 0)) {
bu_vls_free(&output);

[Code] ....

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C/C++ :: Expected Declaration Specifier In For Loop?

Mar 1, 2015

#include <stdio.h>
#include <math.h>
main() {
int n;
int k;
int j;
//gets user input for length of string
printf("Enter the value of n:");
scanf("%d", &n);

[code]......

When I compile my code I get an error saying that I need declaration specifiers in my is_prime subroutine in the for loop.

Here is the line of code it references.

for(j = 2; j < k; j++)

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C/C++ :: Why Implicit Int Approach Taken With No Specifier Only For Global Variables

Sep 22, 2013

I realize that implicit int rule was removed in C99 but gcc still takes this approach by default. I wonder why this happens:

bbb = 5; // legal  
int main(void) {
  aaa = 10; // illegal
  auto aaa = 10 // legal

Inside function a specifier is needed. Error message with no specifier used is:

error: ‘aaa’ undeclared (first use in this function)

Is this because of linkage - bbb variable has an external linkage so compiler knows that we are defining a variable here while inside mean() we need to show compiler that aaa is defined right here, it does not come from external functions?

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C :: Boolean Value Use For If And Else Statements

Apr 20, 2013

Am i using boolean values correctly? our professor wanted boolean value use for the if and else statements.

Code:
#include <stdio.h>
#include <math.h>
#define GRAVITY 9.8
#define LIMIT 500
#define SEC 5

[Code] ....

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C++ :: Negating Boolean Values

Mar 22, 2013

I made some research on how to negate a boolean value but none seemed to work. Ok, so I have the following code:

Code:

#include <iostream>
using namespace std;
int main() {
bool Turn = true;
for (int i = 1; i < 11; i++)

[Code]....

As of now the code prints "XXXXXXXXXX". And I want it to print "XOXOXOXOXO", so I tried 2 different things, which did not work:

Code:

#include <iostream>
using namespace std;
int main()
{
bool Turn = true;
for (int i = 1; i < 11; i++)
{

[Code]...

Code:

#include <iostream>
using namespace std;
int main()
{
bool Turn = true;
for (int i = 1; i < 11; i++)

[Code]...

Ok so I made those changes so that the boolean 'Turn' would change everytime the loop executed. Guess it doesn't work.

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C++ :: Casting A Logical Boolean As Int?

Jun 8, 2013

Let's say I have a product that needs service after 500 hours at 100 RPM. I can dsiplay the remaining hours only as an integer and we only have integer math. Management wants it to display 500 for the first hour, not 499 after the first minute is ticked off. But after a few minutes fullHours will be 499 and partialHours will have some value. I have 3 ways to determine displayHours to suit management and I want to know if the first is ligit.

short fullHours = 500;
short partialHours = 0;
short displayedHours = 0;

// Method 1 - Is is Kosher to cast a boolean as an int? Is TRUE always a 1 or is that a bad assumption?

displayedHours = fullHours + (short) (partialHours != 0);

//Method 2 - Works but some have disdain for the ternary conditional

displayHours = fullHours + (partialHours ? 1 : 0);

//Method 3 - seems a bit pedantic

displayHours = fullHours;
if (partialHours != 0) {
displayHours++;
}

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C++ :: Boolean Function In Turbo?

Jan 9, 2015

Is the boolean function already defined under the default headers? Else, how would I create one? Would this work? :

#define true 1
#define false 0
typedef int bool;
Bool x=true;

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C++ :: 2D Array In Boolean Function

Apr 24, 2014

i have a Boolean function containing 2D dynamic array, it'll retain either 0 or 1, how can i delete the dynamic array?

bool something (int** a,int b, int c) {
int **arr = new int*[b];
for(int i=0;i<b;i++)
arr[i]= new int[c];
if (...) return 0;
else ...
if (...) return 0;
}

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C# :: Split String With Boolean

Nov 19, 2014

I have my Arduino send the following string every second:

69.4,69.4,69.4,69.4,69.4,69.4,8.42,100,100,50,50,20,16,10,14

and i currently have my C# code split it and send the values to corresponding text boxes:

// SERIAL READS:
private void myport_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) {
string RxData = myport.ReadLine();
this.BeginInvoke(new LineReceivedEvent(LineReceived), RxData);

[Code] ....

Now if i were to add true/false values to my arduino string, im not sure to read it. I would like the bool values to enable/disable led jpegs to simulate output status.

rly1_led.enable = newData[15];// if true

Ive tried everything and just cant figure it out. This is my first C# project.

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C :: Writing A Macro That Returns A Boolean Value

Apr 24, 2014

I need writing a macro that would return true/false (1/0) )value. I want to check if a certain element exists in the array. The macro will accept array, its size, and the value to be compared, and must return yes or no. Here is the code that I have written:

Code:
#define EXISTS(T, a, n, val) do {
char ret=0;
T *a_ = (a);
size_t n_ = (n);
for (; n_ > 0; --n_, ++a_){
ret = (*a_ == val);
}
}
while(0)

How can I get the result from this macro.

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C++ :: Reading From Boolean Matrix Class

Feb 18, 2015

Question for coding transivity in c++

a->b b->c then a->c

It should contain a main code reading from boolean matrix class. for ex)input file is

8
0 1
1 2
2 3
3 4
4 5
5 6
6 7

8 is the number of no.

what program should do.
1. check if 0->7 first(0th element)->last
2. check every 5th(5,10,15...) element is to last 5->7

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C++ :: Assigning A Function Using Boolean Operator

Nov 18, 2013

I am writing a code where I have to find out the spot a letter is in. I am getting an error with assigning a function using a boolean operator.

bool is_member(const vector<char> & list, char character) {
for(int i=0; i < list.size(); i++) {
if(character==list[i]) {
return(true);

[Code] .....

My constant vector list is { 'a', 'e', 'i', 'o', 'u', 'y'}. My error comes in on line 20. I am not calling the boolean correctly. If I type in the letter "i". Then the function should output 2 since i is in the 2nd index spot of my vector list. How to fix my error? I am not understanding why my line of code is not working.

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C++ :: Boolean Function Not Returning False

Mar 24, 2014

I have a bool type function and set it to explicitly return false, but I am still getting true as the return.

#include <iostream>
#include <fstream>
using namespace std;
int main(int argc, char* argv[]){
double coeffs[3];
double roots[2];

[code].....

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C++ ::  How To Cout Boolean Result In Words

Dec 11, 2013

So I want to go from having 0 or 1 to having words like false or true. I did it with an if statement earlier today, but I had to get rid of the whole bool thing. I made the variable just a float. But he requires we use bool. Here is my code:

Car y;
cout << "Initial value for the Car: " << endl;
cout << "Age= " << y.getAge() << " years old. The Price= $" << y.getPrice() << endl;
y.setAge(8);
y.setPrice(12000);
y.setRaceCarStatus(true);
cout << "Modified value for the Car: " << endl;

[Code]...

I commented (//) the if statement that I had earlier. If I set RacecarStatus to True, is cout's 1. The starred (*) line right above the comments is the line that I was required to add. I want to cout the actual word true. The one I had this morning won't work anymore.

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C/C++ :: Inputting True For A Boolean Variable?

Feb 7, 2014

My assignment : "Input the answer as the words true or false and put the user's answer in a boolean alphabetic variable."

My code:

bool T;
cout << "Type 'true' for lowercase or 'false' for uppercase";
cin >> T;
if (T == "true") {
cout << "Enter a whole number in decimal base: ";
cin >> dec;
cout.setf(ios::showbase);
cout << "Decimal " << dec << " to Hexadecimal with lowercase: " << setbase(16) << dec;
}

I'm not sure how to get 'true' as user-input as true for bool.

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C# :: Registration Object - Return Boolean Value

Sep 10, 2014

Requirement: the AddRegistration method in the RegistrationDB class should accept a Registration object and return a Boolean value that indicates if the operation was successful

a brief overview. Form with two combo boxes and a button, when you click the button the data from the combo boxes is entered into a table in the connected database...

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C Sharp :: Integer To Boolean Conversion?

Nov 20, 2014

ive written a simple code but throws an error in C#, why is this happen.

    bool inputValue = Convert.ToBoolean(Console.ReadLine());
        Console.WriteLine(inputvalue);
        Console.ReadLine();

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C++ :: How To Program Boolean Union And Intersection

Jun 19, 2014

It involves some discrete mathematics. Any code snippet to get me started?

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C++ :: Evaluating Logical Boolean Expressions

Jan 10, 2013

I am looking for a library to aid me in evaluating Boolean expressions. For example, i have an expression like this:

(1*(5+3)+9*65/5-(354*4565*5643+98) >= 12345) && ( 654*987+123 || (2345 > 23423 && 1 != 2)))

(It can also be much longer!) and would like to evaluate them to a true/false boolean.

There are tons of libraries to calculate the (numerical) result of a mathematical expression, but this is not what i want to do.

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C :: Boolean Value Cross-functional In Game TicTacToe

Dec 11, 2014

Why something doesn't work without setting global variables. I want to know how to deliver values for example my boolean value "ende" (means end) from the function in line 99

Code:
bool pruefeGewinn() or in line 116 Code: bool spielfeldVoll() to the main function for using it there for Code: } while (ende != true); in line 164.

How to return it correctly?

Here is the Code of the game TicTacToe.

Code:
#include <stdio.h> // In- and Output
#include <stdlib.h> // Implementation of many functions
#include <stdbool.h> // Allows in C99 True and False as Boolean
#include <time.h> // Allows using Random by time

/*----------------------- Constants -------------------------*/

#define KANTENLAENGE 3
#define STRING 100

[Code] .....

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C++ :: Vowel Test Boolean Return Values

Nov 8, 2013

I'm trying to test if a character is a vowel. I made a separate function for the test, I'm not really sure how to get my return value to output whenever I call the function from main?

Also, I'm not good with while loops and can't figure out how to get it to continue asking whether or not the user wants to keep entering values.

#include <cstdlib>
#include <iostream>
using namespace std;
bool isVowel(bool);
int main(int argc, char *argv[]) {
char var1, cont;

[Code] ....

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C++ :: How To Test Multiple Boolean Using A Switch Function

Oct 21, 2013

I don't know that a Function is the right word for switch/case but it seems like this would exist, is there a way to test multiple booleans using a switch function?

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C++ :: How To Switch Between Boolean True / False Logic Within Do / While Loop

Mar 25, 2014

I have a hit a snag in a number guessing game program. I was given a half-completed program and told to use functions to complete the missing pieces. It looks unwieldy, but this is how it is supposed to be. I have temporarily made the random guess value visible for troubleshooting purposes.

#include <iostream>
#include <time.h>
#include <stdlib.h>
using namespace std;
int welcome() {
cout << " Welcome to the hi-low game!" << endl;

[code]....

The issue lies within this piece of code:

checkGuess(guess, correct); done = false; //either true or false
} while (!done);
cout << "Congratulations, you got it!" << endl;
return 0;
}

I need to manipulate the Boolean variable done so that it registers as false when the user inputs a number higher or lower than the randomly selected value. However, if the user guesses correctly, done will become true and the program will end.

As it stands now, the program will not terminate, and if I set done equal to true like so:

checkGuess(guess, correct); done = true; //either true or false
} while (!done);
cout << "Congratulations, you got it!" << endl;
return 0;
}

Every number the user inputs will register as correct instead of the one right guess.

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