C++ :: Setting Default Parameter Based On Another Parameter?
Jul 2, 2013
Here's my function definition
bool validateNumber(string& text, int min = 0, int max = -1, bool useMin = true,
bool getValid = true)
The code takes the string text, and checks the make sure that the input is valid and safe to convert and use as a number. However, sometimes there is not min, and sometimes there is no max. The lack of min is done by using the parameter useMin, while the lack of max is done by max < min.
My predicament is the following call:
validateNumber(text, -2);
Now, max will be used, even though I don't want it. Ideally, I would want to do something like... int max = (min - 1), ... but that doesn't work. I also can't check to see if the parameter hasn't been changed (that I know of), because the following call would make it look like it hasn't
validateNumber(text, -2, -1);
So the question is, is there a way to do what I want, without having to add in a bool useMax parameter? Or is this my only option? I don't want to do that for simplicity, but if I have to, I have to.
View 3 Replies
ADVERTISEMENT
Dec 4, 2013
I am developing new project in Qt with existing MFC project . SO in MFC I have a function which uses SYSTEMTime and return CString.
example
CString getTimestampString( void )
{
SYSTEMTIME systemTime;
CString datestr;
[Code]....
PS -> I cant able to make any changes in lib_know as this library is being used by many other projects..
View 1 Replies
View Related
Dec 1, 2014
I faced a compilation error in the following code :
Code:
#include <iostream>
using namespace std;
void addition(int a, int b = 2, int c);
int main()
[Code]......
My question is that when i have called addition() with the 3rd argument, then what is the necessity of having the default argument for the 3rd parameter ?
View 6 Replies
View Related
Dec 4, 2014
Say I have a GetSomething(char type) function which returns two different variables based on what you pass it, like so:
float Flashlight::GetSomething(char type){
if(type == 'x'){
return velocityX;
} else if(type == 'y'){
return velocityY;
} else {
std::cout << "Debug: Programming error getting flashlight velocity
"; } }
On a scale of null pointers to (insert something notably good), how good or bad is this practice? Just asking out of pure curiosity.
View 3 Replies
View Related
Sep 28, 2014
My errors are at the end of the program in two function calls within the definition of the InsertByValue function. g++ does not seem to recognize NumArray as a valid parameter.
#include <iostream>
#include <assert.h>
using namespace std;
const int CAPACITY = 20;
/* Displays the content of an int array, both the array and the size of array will be passed as parameters to the function
@param array: gives the array to be displayed
@param array_size: gives the number of elements in the array */
void DisplayArray (int array[], int array_size);
[Code] ....
View 1 Replies
View Related
Oct 28, 2013
I have a class as below:
// RemoteControlMonitor.H
typedef void (*keyaction)(unsigned int key);
class RemoteControlMonitor {
private:
keyaction rph;
keyaction rrh;
[Code] .....
But I got compile error as below:
RemoteControlMonitor.H:58: invalid type `void *' for default argument to `void (*)(unsigned int)'
rcx1.C: In function `void __static_initialization_and_destruction_0(int, int)':
rcx1.C:54: ANSI C++ forbids implicit conversion from `void *' in default argument
What can I do?
View 1 Replies
View Related
Aug 23, 2013
Code:
#include <stdio.h>
void ASCII_to_EBCDIC( size_t, unsigned char *);
void EBCDIC_to_ASCII( size_t, unsigned char *);
void to_ASCII(unsigned char *);
void to_EBCDIC(unsigned char *);
/* conversion tables */
static unsigned char
[Code] ....
The above snippet is for a buffer/string, where as i want to pass file name as a parameter and want function to process the file line by line?
View 2 Replies
View Related
Apr 17, 2014
How I can delete a parameter in a function .
int *buildTrail(int antIndex, int start, double *pheromones) {
int *trail = new int[tabu];
bool *visited = new bool[tabu];
trail[0] = start;
visited[start] = true;
[Code] ....
If I comment all lines includes visited word , no exception occurs , Otherwise , exception throws.
Simply put , How can i delete visited parameter as long as its role has been finished?
.
.
.
delete visited ;
return trail;
View 4 Replies
View Related
Jan 16, 2014
Unless I'm missing something, it's now possible(ish)? A little concept is below, very rough around the edges. Still though, if this is valid by standard C++, why can't we have built-in support for float / double template parameters?
#include <iostream>
#include <tuple>
template<int Numerator, int Denominator>
struct Float {
constexpr static float value()
[Code] ....
View 7 Replies
View Related
Oct 14, 2014
I have run into a problem which is mostly just an annoyance. I need to know if i can have pass a derived class to a function which has the base class as its parameter. For example i have been creating a program but i have a function which needs to work for multiple classes all derived from the BaseObject class
Code :
class folder : public BaseObject
{}
class BaseObject
{void function(BaseObject B)}
how would i get the following to work:
function(folder)
View 3 Replies
View Related
Sep 8, 2013
What is the "Named Parameter Idiom" in c++?
View 3 Replies
View Related
May 1, 2013
#include <cstdlib>
#include <iostream>
struct tax_node {
char form; // tax form letter
int version; // tax form number
[Code] ....
I cannot seem to get why function print_contents will not work. The couts at the end of the program is just to test that it printed correctly. But, if I need it to print the contents such when print_contents(ptr2) is called. I think it should be tax_ptr in the parameter list but I am not quite sure.
View 1 Replies
View Related
Mar 14, 2013
I want to have a function that has a pointer to an int/double/string so I thought I'd use a void pointer like so:
int someFnc(int a, int b, const void *key){
// take care of converting key into appropriate type in here
}
And when I want to use this function I'd like to be able to do something like this:
main{
...
int myKey;
someFnc(1,2,myKey);
]
But I get a compiler error telling me:
invalid conversion from 'int' to 'const void' -[fpermissive]
Do I need to convert myKey into a void pointer before passing it as an argument?
Why does passing myKey like this work?
someFnc(1,2,&myKey);
View 1 Replies
View Related
Apr 9, 2014
In my raytracer-project I have the following function:
bool hitObjects(Ray &ray, std::vector<Object *> &objects, Vector3& normal, Material *mat) {
double tmin = K_HUGE_VALUE;
double t;
[Code]....
When I try to run this, I only get the message "Material pointer is null". So, somehow the pointer is null after the hitObjects-function is called, even though it isn't inside that function.
View 6 Replies
View Related
Jan 7, 2015
gcc v.8.3 -std=gnu++11
[URL]
I'm trying to pass a function as a parameter and failing. It seems simple, until I get the error messages.
Here is the code:
class MinimalSolver {
typedef double (*func)(double sum, double char);
void driver();
[Code]....
View 2 Replies
View Related
Nov 16, 2014
I want to create events and then, functions which are subscribed to the event can access information about the event. For example, in Class 2 below, I want it to be able to access things such as touch.position, etc. of class 1.
Class 1:
public delegate void TouchEventHandler (EventArgs e);
public event TouchEventHandler TouchBegan;
public Vector2 touchPosition;
void Update () {
if (Input.touchCount > 0) {
[Code] ...
Class 2:
void OnTouchBegan (EventArgs e) {
Debug.Log ("Ran");
}
View 5 Replies
View Related
Nov 24, 2014
I am writing a text-based rpg and I'm having some issues trying to pass the player struct to a function. First, here are the relevant code snippets. Also, Player.c and Player.h aren't completed but the relevant function is. I just run tests every now and then to see if everything is working right.
Monster.h
#ifndef MONSTER_H
#define MONSTER_H
#include "Weapon.h"
typedef struct Player;
typedef struct {
char* mName;
[Code] ....
The errors are:
1. line 33 in Monster.h, the void Attack_Monster_Types(Monster* m, Player* p) the ide says missing ')' before '*', missing '{' before '*' and 'Player' name in formal parameter list illegal
2. line 18 in main.c when the attack function is called. it says 'Attack_Monster_Types' Undefined; assuming extern returning int.
I believe I have all the right headers included so I'm not sure what to do ....
View 13 Replies
View Related
Oct 1, 2014
Where is problem in my code, it is a flappy bird. I dont know why put me that problem when click Start on game show me on 99 line error 'maxValue' must be greater than zero. Parameter name: maxValue
I copy exception to clipboard
System.ArgumentOutOfRangeException was unhandled
HResult=-2146233086
Message='maxValue' must be greater than zero.
Parameter name: maxValue
Source=mscorlib
ParamName=maxValue
StackTrace:
[Code] .....
View 6 Replies
View Related
May 17, 2013
void foo(FILE *f1, FILE **f2) {
fputs("...", f1);
fputs("...", *f2);
} int main(void) {
FILE *fp1 = fopen(...),
*fp2 = fopen(...);
if(fp1 && fp2) {
foo(fp1, &fp2);
...
}
...
}
Forever, I've passed FILE objects into functions like the first parameter; I've never had an issue reading or writing files using that form - no file errors, no compiler warnings, etc. Recently, I saw the second parameter form, and wondered why that was?
I still don't quite get this part of pointers. What's the second parameter form doing differently than the first when the first version *appears* to work as intended??
View 6 Replies
View Related
May 26, 2014
difference between an argument and parameter...understanding the difference between these two.
View 2 Replies
View Related
Oct 6, 2014
How come when we pass an array as a parameter to a function, the entire array is copied and is available to function?
View 1 Replies
View Related
Oct 19, 2013
I want to alter a string inside a function, but it is not working.Here is the function:
Code:
#include <stdio.h>
void test (char *ch){
ch[0] = 0;
ch[1] = 1;
ch[2] = '';
}
[code]...
View 2 Replies
View Related
Sep 18, 2014
I have the defined a class Seconds with a template<int,int> constructor. Unfortunately, I can't seem to get an instance. Here's the class :
class Seconds {
public :
template <int num, int den> Seconds(long int);
}
And when I try to instantiate it :
Seconds *millis = new Seconds<1,1000>(30); // template argument deduction/substitution failed:
// couldn't deduce template parameter ‘num’
Is it not the right way to call the constructor?
View 4 Replies
View Related
Aug 20, 2013
Theres a class named "A" which has got a static function named "sfA".Now I instance an object of class A and call a method from A called "fA".
The method fA calls sfA. And now the issue is: i need the value of a member from the object which called fA respectivly sfA, inside sfA.Is there a smarter way to get the value of the member as to declare an new parameter for the sfA? sfA has to be static.
View 4 Replies
View Related
Jan 11, 2015
Is there any function which can return parameter list of a function.
For example : get_param(f(int x,char y )) return parameter x-> int y-> char
and f_name ->f
View 3 Replies
View Related
May 2, 2013
Write a program that inputs 10 integers from the console into an array, and removes the duplicate array elements and prints the array. By removing, I mean that you should make it appear as if the elements hadn't been there. You may assume that all the integers are between 0 and 100, Write at least 1 function in addition to the main function, and pass an array into that function as a parameter. e.g.
Please enter your 10 numbers: 1 2 3 4 5 6 7 8 9 10 The array contains: 1 2 3 4 5 6 7 8 9 10
Please enter your 10 numbers: 1 1 3 3 3 6 7 8 9 9 The array contains: 1 3 6 7 8 9
Please enter your 10 numbers: 1 1 1 1 1 1 1 1 1 1 The array contains: 1
The bolded area is where I'm having trouble. How I can go about doing this, passing an array into the function as a parameter?
Here is my code:
#include "stdafx.h"
#include <iostream>
using namespace std;
int main () {
const int MAX = 10;
int a[MAX] = {0};
int i;
[Code]...
View 5 Replies
View Related
