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.
View 10 Replies
ADVERTISEMENT
Jan 27, 2014
I'm trying to assign a value to a member of a struct that I called via an overloaded [] operator. I have the following code for the struct:
typedef struct {
float r, g, b, a;
float operator [](int pos) {
switch (pos) {
[Code] ....
And what I wish to do is
MyStruct a;
a[0] = 0.5;
Is it possible with a struct? How to express this to search engines so I haven't been able to find anything about it. If this is not possible with a struct, is there a way to define something that can do all the following things:
SomeStruct test = {0.5, 0.5, 0.5, 1};
test.g = 1.0;
test[0] = 0.0; // test[0] would be equivalent to calling test.r
float somevalue = test[3]; // test[3] would be equivalent to calling test.a
I hope I've been sufficiently clear.
View 2 Replies
View Related
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;
View 3 Replies
View Related
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;
}
View 3 Replies
View Related
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].....
View 7 Replies
View Related
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?
View 1 Replies
View Related
Oct 21, 2014
The question is to write a recursive boolean function that compares two stacks and returns true if they are identical. This is where I get stuck:
If the top items of both stacks are the same, the recursive call always returns true, because 'true' is saved on top of the return stack.
Here is my code:
template<class Type>
bool identicals(stackType<Type> s1, stackType<Type> s2) {
if(!s1.isEmptyStack() && !s2.isEmptyStack()) {
if(s1.top() != s2.top())
[Code] ....
View 2 Replies
View Related
Aug 2, 2014
I have the following:
int Allocate(int, int *);
main() {
int *Pointer;
int Elements = 25;
// this works just fine - as expected.
Pointer = (int *) malloc(Elements, sizeof(int));
// This DOES NOT - The value of Pointer never changes.....
[code]....
View 2 Replies
View Related
May 13, 2013
I'm trying to create an array of function pointers and then assign compartilbe functions to them, so I can just call *pf[0](xxx);
The functions are all of the type
void func01(unsigned char*, int, int)
how would I create an array of function pointers and assign the address of the functions to them? So I could call them like
ptrToFunction[i](charBuffer, 10, 20);
I've read a bit on line and I thought I could do it but so far I've failed.
It seems trivial and I feel I'm close but close isn't good enough.
I'd like to assign the fuction addresses like this:
for (int i=0; i<10; i++)
if (i==1)
ptrToFunction[i]=func01;
if (i==2)
ptrToFunction[i]=func02;
etc.
The actual logic is somewhat different than this but this close.
View 4 Replies
View Related
Apr 3, 2013
why can't << operator be overloaded as a member function is it because that is the way c++ is written and you just can't or is there another reason because I'm confused.
View 2 Replies
View Related
Sep 17, 2013
I don't exactly know how to test my ==friend function in my main.
Here is my .h file:
#include<iostream>
using namespace std;
class Car{
public:
Car();
Car(int yer, string mke);
[Code] ....
View 3 Replies
View Related
Jul 24, 2013
What is the role of friend function in this program? Is it even executed here?
#include <iostream>
using namespace std;
class loc {
int longitude, latitude;
public:
loc() {} // needed to construct temporaries
[Code] ....
View 2 Replies
View Related
Feb 4, 2014
I am writing the overloading operator function (prefix ++) according to my book.. but it doesnt work !!!!!!
But if i write:
void operator++() {
++x;
}
It works !!!!!
Here is my code according to the book that doesnt work as it should:
#include <iostream>
using namespace std;
class things {
int x,y,z;
[Code] ....
View 2 Replies
View Related
Feb 24, 2015
I have recently come across a function call that I do not understand. It uses the arrow operator for a function call, twice, and I don't understand.
Code:
static inline void b43_write32(struct b43_wldev *dev, u16 offset, u32 value)
{
dev->dev->write32(dev->dev, offset, value);
}
I see that the function itself does not return anything but calls another function. The main difficulty I have is with the "dev->dev->" operator, where dev, I expect is a pointer to a structure.
View 8 Replies
View Related
Aug 23, 2014
Say I have a class that requires dynamic allocation to implement a few of the operators. Take "+" for example; I need to create a new object to hold the sum of the two parameters whose size is not known at compile time.
I'm pretty sure the standard way to indicate a failure inside the overloading function would be to throw an exception. However I am currently involved in an embedded(ish) project where the spec. says no exceptions are to be used.
I think I have 2 options:
1. Return an "invalid" object (with a flag indicating an error has occurred) and check for this after each operation.
a = b + c
if (a.err)
// handle error
or
2. To forsake operator overloading entirely and think up a new way of doing things where all functions that involve dynamic allocation can return error codes. but this seems rather terrible too as I may end up with something like:
objA a
if (add(&a, b, c) == -1) // assuming b and c are initialized before this snippet starts
// handle error
Is there a number 3 that I haven't thought of? It seems that not allowing exceptions is fairly common even in the non-embedded world [URL] so how is this normally done? or is operator overloading usually avoided when exceptions are not allowed?
View 3 Replies
View Related
Jul 29, 2013
I have a class and I would like to be able to pass an extra parameter to the function that is executed.
BigInt operator / (BigInt N,BigInt D) {
...
}
is what I have now. but I would like to do something like this. so the default value for a is 10. and if the user does something like N/D (12) Then the value of a is 12.
BigInt operator / (BigInt N,BigInt D, int a=10) {
...
}
View 2 Replies
View Related
Aug 24, 2014
How I can let the user input a certain operator into this calculator function?. I would like to use cin to input the operator if possible because it is one of the only input commands I know.
// Calculator.cpp : Defines the entry point for the console application.
// Calculates the value of two numbers based on the four main operations.
#include "stdafx.h"
#include <iostream>
int add(int x, int y);
int subtract(int x, int y);
int multiply(int x, int y);
int divide(int x, int y);
[Code] ....
View 1 Replies
View Related
Sep 2, 2014
string concatenation using operator overloading function using + operator. i wrote the proto pls explain body of the function.
class A
{
char *p1,*p2;
public:
A& operator +(A &obj1)
{
-----
-----
}
};
/>
View 3 Replies
View Related
Dec 26, 2014
I want to overload prefix and postfix increment(++) operators with friend function. I also have to use the constructors for this. How can I do this? in C++
View 4 Replies
View Related
Dec 26, 2014
I want to create a program that shows the total of 2 subjects & percentage of student using binary operator overloading with member function in C++.
View 10 Replies
View Related
Mar 22, 2013
I'm doing a refresher for C++ and have gotten to operator overloading. I'm trying to perform an operator overload with the insertion (<<) operator, but I have encountered a problem.
Here's my class [In a header file "Shinigami.h"]
#include<string>
namespace K{
class Quincy;
class Shinigami{
friend std::ostream& operator<<(std::ostream&, const Shinigami&);
[Code] .....
If the operator function is a friend of the 'Shinigami' class, why doesn't it recognize any of it's private members? I need it to be in this file because I'm doing a bit of association with the 'Quincy' class.
I thought it was the namespace, but I included that.
View 9 Replies
View Related
Feb 19, 2015
Im using a recursive function to sort array. The decrement operator is used to eventually get to base condition in function. Used debugger the size-- expression is not decrementing. I figured out how to fix it but dont quite understand it.
[coed]
#include "stdafx.h"
#include <iostream>
void selectionsort(int [], int);
int main()
{
using namespace std;
const int arrysize = 10;
[Code]...
View 3 Replies
View Related
Apr 10, 2014
Consider the class specification below. Write the prototype (i.e. header) of a member function to overload the insertion operator (i.e. <<). The << operator is to output the data members of an instance of class StudentTestScores into an output stream. Your definition should allow for chaining of output operations (e.g. cout << x << y; where x and y are of type StduentTestScires).
#include <string>
using namespace std;
class StudentTestScores{
private:
string studentName;
float *testScores; // used to point to an array of test scores
int numTestScores; // number of test scores
[code]....
View 1 Replies
View Related
Jun 11, 2013
I have a class matrixType that has some overloaded operators (+, -, *, and <<). With a view to having clearly-delineated, perfectly-formatted, four-sided matrices, as shown below:
A = 1 2 3
4 5 6
7 8 9
or
A + B = 1 2 3
4 5 6
7 8 9
and NOT this jagged ones shown below:
A = 1 2 3
4 5 6
7 8 9
or
A + B = 1 2 3
4 5 6
7 8 9
,
I want a scheme in which the string literals (A, A+B, etc.) could be passed as parameters to the overloaded stream insertion (<<) operator function so that I could use the string’s length to determine how much offset from the display screen’s left to apply to each matrix’s row (by using the setw() function). However, I do know that the << operator is a binary operator, meaning the function cannot take more than two parameters: that is what compounds my problem!
View 10 Replies
View Related
Aug 1, 2014
Code:
class VAR_EXPORT VAR {
public:
};
VAR_EXPORT QDataStream &operator>>(QDataStream &p_stream, QSharedPointer<Data>& p_data)
[Code] ....
Above compile and build ok. But when i build another library that use the above, i was shown with all errors complaining operator << and >> definition of dllimport function not allowed
error C2491: 'operator >>' : definition of dllimport function not allowed
error C2491: 'operator <<' : definition of dllimport function not allowed
View 1 Replies
View Related
Aug 17, 2014
I'm having trouble understanding this error I'm getting in my copy constructor and my bool operator in my class methods file.
error C3867: 'Grid::isLegalMove': function call missing argument list; use '&Grid::isLegalMove' to create a pointer to member
grid.cpp
#include <iostream>
#include "Grid.h"
#include "DUPoint.h"
#include <vector>
#include <sstream>
using namespace std;
Grid::Grid() { }
[Code] .....
View 1 Replies
View Related
