Which is more efficient in functions? Returning values or using pointers to redefine variables passed as arguments?
I mean either using:
void ptr_Func(int *x)
{
*x = *x+1
}
or
int ptr_Func(int x)
{
return x + 1;
}
In terms of speed, memory use etc.I want to know general efficiency, I know it will obviously vary with different uses and circumstances.
Write a constructor that initializes a new inventory object with the values passed as arguments, but which also includes a reasonable default value for each parameter.
#include "stdafx.h"
#include <iostream.h>
#include <stdio.h>
#include <string.h>
class inventory {
[Code] ....
I am not trying to get my homewotk done, just to understand my errors. It complies without problem. But doesn't run.
My project is say that it has memory leaks. When I view it in the debugger, it shows the correct values being passed to the pointers.
Code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
bool ConfigGetEntry( char *pcFile, char *pcNameMust, char* &pcResult ) {
char pcBuffer[ 512 ];
[Code] ....
Its saying that i have memory corrupting at..
Code:
if ( !ConfigGetEntry( pcFile, pcName, pcRet ) ) return _strdup( pcDefault );
Also is it normal to have a bad pointer then point data into it to then clear that of the bad pointer. To have valid data now in that pointer.
preventing a buffer overflow when dealing with strings being passed as arguments.
If I have a function prototype such as:
Code:
void foobar(char *bar);
That argument bar - is intended to take a pointer to a buffer of x characters in length. Inside that function, I can't get the size of that buffer, as bar is now just a pointer to a char. I COULD just make the user of this function pass a length parameter, but there is no guarantee that would be correct. Is there a bullet proof way of detecting that the user has provided a buffer that is too small?
I am writing a code that creates a deck of cards using a doubly linked list. One function, newDeck(), is made to create a new deck if the user wants. I don't have any problems creating the deck and it all seems to work fine, but when I run the whole program and a separate function needs to utilize the nodes in my deck, I get an error. Trying to find where there was a problem, I tried displaying the values of a card node in random parts of my code. At the end of the newDeck function, after the whole deck has been created, the card still displays correctly, yet when I return back to main immediately after newDeck has been called, I noticed that the values of my cards changed to either random values or they became null. I found this strange because in between the end of my newDeck function and at this point, there is no extra code so it doesn't seem as if there is any way the pointers could have been changed. Maybe It's because I don't have a complete understanding of pointers yet but is there any way that pointers can change values when returning from a function to main?
newDeck(head, tail, n); //this is how I call the function from main.
void newDeck(Card* head, Card* tail, Card* n) //this is my function body
{
for (int i = 0; i < 4; i++)
{
[Code]....
We're assigned a project working with classes and fractions. My goal is to display a fraction in proper from based on 2 arguments passed to a class member function proper();
My strategy was to utilize the greatest common factor between the 2 arguements, then divide both the numerator and denominator by that number and then it would display.
The program actually runs, but only seems to divide the numerator and not the denominator. This in return makes my other class member functions have incorrect comparisons and sums.
Code:
#include<iostream>
#include<conio.h>
class Fraction {
friend void compare(Fraction a, Fraction b);
friend void sum(Fraction a, Fraction b);
[Code] ....
I am going to read some codes about image processing and I need to understand functions like this one below?
BOOL Trans_Geo_Affine(CImage *pImgSrc, CImage *pImgDst, BOOL bMatrix,
BOOL bHvInversed, double fScale_xx, double fFlex_xy, double fSkew_yx,
double fRotate_yy, double fTx, double fTy, int nInterpolation, BOOL bResize, BYTE cFill)
[URL]
two parameters, CImage *pImgSrc and CImage *pImgDst. I think they are class pointers and the function is passed by reference. What should I learn to understand this function and its parameters? How should I use this function? how to use the function with two parameters CImage *pImgSrc and CImage *pImgDst.
What the code below is not doing is returning a value for item to my variables (item1, item2, etc..) I'm not sure how I can make a function prototype that will ask for input and basically recycle after going through the program to a new value for each item. I also need to input individual tax for each item. I will also post it in this message:
double tax, item,salesTax;
double cost(double);
double CalcSalesTax(double);
main(){
double total,item1, item2, item3, item4, item5, tax1, tax2, tax3,tax4,tax5;
[Code].....
I have this code:
tgaManager.fileWriter.put((unsigned char)min(blue*255.0f,255.0f)).put((unsigned char)min(green*255.0f, 255.0f)).put((unsigned char)min(red*255.0f, 255.0f));
that should pass the value decided by the min function to an ofstream object, filewriter, that call the put method to print chars in a tga image file. When I open the file, all I see it is a huge black screen. You may be thinking that the values of blue,green and red are all zero but it is not the case.
With this code:
if (x==50 && y==50) {
cout << "Min BGR: " << endl;
cout << min (blue*255.0f,255.0f) << ' ' << min (green*255.0f,255.0f) << ' ' << min (red*255.0f,255.0f) << ' ' << x << ' ' << y << endl;
I get: Min BGR: 9.54167 29.9188 47.8701 50 50
How to use a function twice to calculate two different variables. How to have a function compute the city tax, then it uses the function a second time to compute the county tax.
My program compiles, and runs fine, however it only outputs the city tax calculation. It seems it never attempts to calculate the county tax.
One thing: All of the directives I used is what we are limited to, no more, no less. He requires a set format and will dock points of you use anything but those directives and void main().
Here is my code so far:
/* function for city tax calculation */
#include <iostream>
using namespace std;
#include <string>
#include <cstdlib>
#include <cmath>
#include <iomanip>
const double city_tax_rate=0.03;
[Code] ....
I am using Visual studio 2010.
I am trying to return 2 numbers from my function to main(). They are both read in from an input file but it is not working out.
#include <fstream>
#include <iostream>
using namespace std;
ofstream outfile;
void heading(int);
int stuid(int,int);
[Code] ....
Ive been getting an odd error with this code when I try to compile it, as well as Im not quite sure as how to return my variable "compType" as a char type.
Main
#include <iostream>
#include "Shape.h"
#include <iomanip>
#include <cmath>
using namespace std;
void inputShape( char shape)
[Code] ....
I'm having some problems with a function. The function is supposed to find the two largest values in an array.
Code:
void find_two_largest( const int *a, int n, int *largest, int *second_largest){
largest = a;
int temp;
second_largest = a;
for ( int i = 1; i < n; i++){
if (*(a + i) > *largest){
temp = *largest;
[Code]....
I don't see any mistake with the code of the function, but when I try to call it inside my program it only returns 0 for both largest and second_largest.
Code:
int *find_middle( int *a, int n);
void find_two_largest(const int *a, int n, int *largest, int *second_largest);
int main()
{
int n;
[Code]...
Do I have to declare the variables largest and second_largest as normal integer variables and then pass their addresses as arguments to find_largest or is that incorrect?
I have struck with issue regarding process arguments
Part of my code below:
ProcessStartInfo info = new ProcessStartInfo();
info.FileName = MsiTran;
[b]info.Arguments = "-a """ + MSTpath + "" " + MSIpath"";[/b]
MSIpath and MSTpath are already defined string variables.
I get error: only assignment call increment decrement .....can be used as statement
How can setup my arguments to cal the pre-defined variables.
There are, or course, better ways to do this, but I need to stick to some rules:
(1) Use only pointer variables and not arrays or structs.
(2) Use the three functions shown--regardless of easier methods.
The program should ask for some input, operate on those numbers, and then display the results. I know I am confused over these things:
(1) All that syntax using '*' and '&' or neither.
(2) How to use the char type correctly.
(3) How to use a char type input as an operator (a + b).
(4) How to use the pointer of the operator variable (+,-,*,/) in an actual equation.
Code:
#include <stdio.h>
#include <stdlib.h>
// *** Prototype Functions ***
void Post_Results (float*);
void Calculate (float*, float*, char*, float*);
void Get_Numbers (float*, char*, float*);
[Code]......
Say I have a function pointer with this definition:
void ( *pressFunc ) ( void*, void* );
And i did this function:
void functionWithOneArg ( void* testPtr );
And i did this
pressFunc = &functionWithOneArg;
One. Would C actually let me do this? ( Assigning a function with one argument to a function with two )
Two. If so, what would happen to the second argument that is passed the function when its called? Does it just get 'cut off' and only the first argument is passed?
I always have confusions while using pointers with functions both as arguments and as return type.
View 1 Replies View RelatedCode:
void Class1::Func(shared_ptr<type1> parameter)
{
}
or
void Class1::Func(const shared_ptr<type1>& parameter)
{
}
or
Should I ever pass arguments/parameters to other objects using shared_ptr's or raw pointers?
Firstly I don't really know if this is possible.
This is my Class Diagram: [URL]...
github: [URL]...
I want to redefine the price object of the Book Class. However price is defined at Products Class.
I want the price value change according to the marker value, which is a Book attribute.
If the marker is blue, price gets a value of 10 (e.g.), if it has another value, price is equal to 20.
I am currently doing a bodyfat calculator for a course in school.I'm having a problem getting an output returned from my while loop, which determines the user's gender by user input.My function (outside of main) is currently:
Code:
char gendercheck(gender){
while (true) {
gender = _getch();
if (gender == 'M' || gender == 'm') {
system("cls");
printf("Your selected gender is male.");
break ;
[code]....
My failed tries include "return gender" and "return genderpicked" statements in both the if-functions and the loop itself, which I have deleted since that didn't work. My goal is to get a character stored in gender, so that I can use the information of the user's gender in my main function from this point and onwards.
MY MAIN IS:
Code:
int main() {
char *genderpicked ;
char gender ;
genderpicked = &gender ;
[code]....
I am working on this program below. The problem I am having is trying to return totalDays to the main. In the numOfDays() function there is a for loop that adds the totalDays (totalDays = totalDays + days). I have just been getting errors in returning the correct amount of totalDays to the main from the numOfDays function.
#include <iostream>
using namespace std;
int numOfEmployees();
int numOfDays(int);
int main() {
int totalDays = 0;
[Code] ....
I would like to return multiple values from one function to access in different functions. For example:
int function1(//what goes here?)
{
int a ;
a = 1 + 2 ;
int b ;
b = 3 + 4 ;
return (what goes here if i want to return the value of a and/or b to use in another function?) ;
void function2()
{
//now i want to use the value of a here to use in an equation, how do i do that?
//now i want to use the value of b here to use in an equation, how do i do that?
}
I have an assignment in my C++ class that is to create a menu based coffee shop program. Here is what I have so far:
#include<iostream>
#include<cmath> //doubt this is needed but i added it just in case
using namespace std;
[Code]....
I have made an application and I have basically solved everything. But the only problem is that I am using global variables because it felt like the smoothest, so my program is built on it.
But now I've read around and I understand that you should not use these(?). Do you think pointers is the best think to use instead?I have previously declared my board array and some variables as global and I want them in alot of functions.I have read and understand the procedure for the use of pointers so I can use my int's in the other functions by doing like this? Code: #include <stdio.h>
int justprint();
int main()
{
int Row = 2;
int Column = 2;
int *pRow = &Row;
int *pColumn = &Column;
[code]...
But how do I do it with an array like this one? If I declare it in the main function, and then want to use it in other functions.Or are there better, easier solutions?
Code: char game[3][3]={{0,0}};
So I have a function like the one below
bool get_array( float input_param, vector<int>& output_param ){
// some code that handles output_param output
if( error ) return false;
}
So basiclly this function must return 2 value well one of the value is just a bool returning whether the procedure doesn't fail at some point or not.
is there any better way to write this function ?
I am posting this simplified piece of code that is a bit confusing for me. There are two functions that I call. One shows the expected results but the result of the other one rather puzzles me.
//#define defineVecTyp Vec3f
#define defineVecTyp float
template <typename vecTyp>
vecTyp buildLaplacianPyramid(cv::Mat inputmat) {
vecTyp lapPyr;
[Code].....
Calling the function sum1 does not change the values stored in the variables val1 and val2. The output of the program is as follows:
val1= 1 ## val2= 10 // before the call of function sum1
val1= 1 ## val2= 10 // after the call of function sum1
sumOfVals= 22
This is quite obvious and as expected and I just pasted this piece of code as an example for better clarification.
However, if I call the function buildLaplacianPyramid and apply a function for Gaussian Blurring, this also effects the cv::Mat passed to the function. The line imshow("M1, after buildLaplacianPyramid",M1); therefore shows an image that is blurred. Since I am not passing a pointer to the cv::Mat I do not understand why this should be happening. I was assuming that there would be a copy of the cv::Mat M1 to be used within the function. Therefore I was expecting the cv::Mat M1 to retain its original value. I was expecting that all changes applied to cv::Mat inputmat within the function would not have any influence on the cv::Mat M1. Just like in my other example with the sum.