C++ only allow addition and subtraction operation with pointer .why multiplication and division is not allowed? Then how to perform multiplication and division with pointer
View 3 Replieswhy are the arithmetic operations like division(p/q) and multiplication(p*q) invalid on pointers?.here p and q both are pointers .
View 6 Replies View RelatedI have to build a program that calculates the remainder of the expression
(2^10)!/((2^10-500)! * 500!)
when divided by 10^9+7
where x^y = x*x*x*x...*x (y times)
and x! = x*(x-1)...*1
How can I do that? I know how to calculate the remainder of x! and the remainder of y!, but I do not know how t calculate the remainder of x!/y!. I can´t even store this in a variable because x! is very large.
At one point in my C++, non-CLR program, the following code:
Code:
unsigned int size = 3;
float maxX = (float)(int(size-1))/2.0f;
std::cout << maxX;
outputs 107. Is it something about a conversion from unsigned int to float?
I heard that the speed of floating point multiplication is much faster than division. Is it still the case today?
View 14 Replies View RelatedHere is the pseudocode,
Code:
class myDX9Widget {
std::vector<Object*> m_vRenderObjects;
};
class Object {
};
class Lorry : public Object {
Activity *activity;
[Code] .....
Don't worry about the exact syntax here, I'd like to concentrate, on a conceptual level, why the line
lorry->Owner->m_vRenderObjects.push_back(pallet);
is not allowed
lorry is regarded as "Pointer to incomplete class"
#include <iostream>
#include <string>
using namespace std;
[Code]....
I'm working on a short program to calculate the mode of a vector of ints. I am new, so not extremely familiar with pointers, and passing items to functions. This is something I've struggled with (obviously, or I wouldn't be here). I am currently getting the following error when I try to compile this program using g++:
warning: pointer to a function used in arithmetic
I receive this error for the following lines: 66, 73, 75, 81.
I am not using pointers here so I do not understand why this error crops up, much less how to fix it. Here is the code I am struggling with:
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <limits>
using namespace std;
vector<int> getModes(vector<int> userValues);
[Code] ....
The errors are on lines 54, 61, 63, and 69
I am stucked in a problem of overloading arithmetic operators such as "+,*" for a class in the form
class Point {
int N; // dimension of the point
double *Pos; // length of N
}
My assign operator is :
Point& Point::operator= (const Point& pt) {
N= pt.N;
if(Pos == NULL) Pos = new double[N];
memcpy(Pos, pt.Pos, N*sizeof(double));
[Code] ....
The add operator "+" is:
Point operator+( const Point& pt1, const Point& pt2 ) {
Point ptr = Point(pt); // this is a constructor
for (int i=0; i<pt1.N; i++) ptr.Pos[i] += pt2.Pos[i];
return ptr;
}
Based on the above overloading, What I am going to do is :
P = alpha*P1 + beta*P2; // alpha and beta are double constants, P1 and P2 are Points objes
It is ok with Intel C++ 14.0 compiler, but does not work with the microsoft visual c++ 2012 compiler in debug mode in visual studio 2012.
I stepped in those operators and found that visual c++ compiler deconstructs the ptr in operators "*" and "+" before its return while intel c++ finished the operation P = alpha*P1 + beta*P2; and delete those ptrs at last.
Portability of my operator overloading is worse. How to get those arithmetic operators overloading for class with pointers in it.
Dynamic memory allocation and pointer arithmetic with char arrays.
The class was given to me in a very basic skeleton form with prototypes but no implementations, along with a test function to test my implementations. I CAN NOT use any C String functions in this assignment.
The part of the program which is troubling is the append function, which just appends a parameter string215 object to the end of the current string215 object.
// Add a suffix to the end of this string. Allocates and frees memory.
void string215::append(const string215 &suffix) {
char *output = new char[str_len(data)+suffix.length()+1];
for(int x = 0; x < str_len(data); x++) {
*output = *data;
[Code]...
This portion of the code is tested in the 13th test of the test function as shown here:
string215 str("testing");
...
// Test 13: test that append works in a simple case.
curr_test++;
string215 suffix("123");
str.append(suffix);
if (strcmp(str.c_str(), "testing123") != 0) {
cerr << "Test " << curr_test << " failed." << endl;
failed++;
}
Here is the description of the append class: Add the suffix to the end of this string. Allocates a new, larger, array; copies the old contents, followed by the suffix, to the new array; then frees the old array and updates the pointer to the new one.
My program aborts at the very end of the append function execution with the error message:
Debug Assertion Failed!
Program: [Source path]dbgdel.cpp
Line: 52
Expression: _BLOCK_TYPE_IS_VALID(pHead->nBlockUse)
...
Abort || Retry || Ignore
Here's a pastebin of the .cpp and .h file for this program
string215.cpp: [URL] ....
string215.h: [URL] .....
I have the following details
double x= 1.5
double y= -1.5
int m= 20
int n= 4
my question is 5 * x - n / 5 at which what would n / 5 equal to, I think its zero since its integer division? or would the 5 be considered a real number?
I have union of pointer.
union {
short *two_int;
int *four_int;
double *eight_real;
char *one_ascii;
// void *v;
};
We have write function which write into file.
fwrite (r.one_ascii, 1, i, outstr);
I found one thing,When we write function, we fill only four int in following way.
r.four_int[0] = x + xoff;
r.four_int[1] = y + yoff;
So my question,we fill four_int but write one_ascii only.As is it union of pointer. So it does not matter. I am using 64bit machine and do not have any issue in 32 bit machine.
For more information: [URL] ....
what I do I cannot get a division to work:
Code:
//END RANGE INPUT
long double End;
printf("
Please enter the start of the range (Lower Bound):
");
[Code]...
No matter what I input for the values of 'Start', 'End' and 'Interval', the value of 'SizeL' always seems to be -2.
I want to find the remainder of the division between a and b, but without using the reminder operator a%b.I thought to subtract b from a as long as a>b, that will give the remainder, but I don't know how to write it in code.
View 11 Replies View RelatedHow do i get this with decimal part?:
for(i=1;i<=4;i++){
printf("%d
",m);
s = s + m/i
m = m + 2;
}
m/i?
Question about instead of using the division operator to display the output of user"s input....
View 4 Replies View Related#include<iostream>
#include<cstdio>
#include<list>
[Code]....
In the last line "graph.edge{x,y,w}" it says typename is not allowed? I have used nested class edge and pushing vertices and their weight in elist vector which is of type edge.
I am trying to get a program to take two files and place them into a third file. I have searched all over this website looking for a solution and i can seem to find one.
My issue is that i keep getting an error 'incomplete type is not allowed' as well as 'no operator matches these ">>" these operands.'
#include<iostream>
#include<string>
#include <sstream>
using namespace std;
int main() {
string filename1;
[Code] .....
So, I ran into the above error. I can't post the actual code, but here is the setup... I have four classes: A, B, C, and D.
A.hpp
Code:
class A {
public:
virtual void foo( D& bar );
[Code] .....
In A.cpp I implement foo and use bar in a similar manner as shown in class C. The difference here is that in A.cpp I also include the header for the D class. I am a bit confused why I can pass bar to B::foo() and that works fine, but if I try to access bar in C::foo, I have issues. Currently I am just including D.hpp in C.cpp.
So I am using Visual Studio 2012 Professional, this is C++ code. I am just trying to get the remainder from a very simple division. Nothing difficult, heres the code:
double getProbability(){
int rd = random();
int max = numeric_limits<int>::max();
double result = rd % max;
cout << "Probability: " << result << "
";
return result;
}
When I look at the values in debug I get:
max 2147483647
rd 1804289383
result 1804289383.0000000
That is completely wrong. The answer should be 0.840188. What is going on here?
random() just returns a number from a vector that was prepopulated with "random" integers. Not really random, but that isn't all that important. What is important is why on earth is a % operation returning such a huge number. I assigned the values to variables so I could look at them in the debugger. I know I am going to probably get a thousand different ways that I could do this "better" but again, that isn't what I am looking for. I would just like to know why the % operation is doing what it is doing?
I have an enum like:
Code:
typedef enum mac_type_e{
STATIC_MAC,
BLACKLIST_MAC
} mac_type_t; and I want to use this type in a structure that's declared like:
Code:
typedef struct lan_mac_s {
UINT16 lanmacid;
enum mac_type_t lan_mac_type_pp;// user mac type per port, 20 mac_type_t array, 0 = static, 1 = blacklisted now,
The compiler tells me:
Code:
incomplete type is not allowed
enum mac_type_t lan_mac_type_pp;// user mac type per port, 20 mac_type_t array, 0 = static, 1 = blacklisted
But if I remove the preceeding "enum" keyword, it compiles fine.
this is my header file
#ifndef Header_H
#define Header_H
#include <iostream>
#include <string>
using namespace std;
class CurrentAccount{
[Code] ....
The problem i m facing now is the CurrentAccount class display is showing error inherited member is not allowed....
When declare and assign an instance of a user-defined struct in a function. And the struct (theStruct) is not declared in the same header file as the function (theFunction). Like this:
files:
"A.h": declares the struct in a class (theClass)
"A.cpp": implements the struct
"B.h": declares the function
"B.cpp": implements the function, error here
I think making the instance (inst) a reference might solve this. But the instance is assigned to a return value from a function (returnFunc). Like:
void theFunction() {
...
theClass::theStruct inst = returnFunc(...);
//returnFunc() returns an instance of theStruct
//the error is at 'inst'
...
}
What do you think?
I'm going from section 7.1 where it is stated that:
Standard wrote:A declaration occurs in a scope (3.3); the scope rules are summarized in 3.4. A declaration that declares a function or defines a class, namespace, template, or function also has one or more scopes nested within it.
Jumping to section 3.3 we find that there exist block scope, function prototype scope, function scope, namespace scope, class scope, enumeration scope, and template parameter scope.
I find nothing that states that static_assert declarations cannot be used in any of those scopes, yet only block, function, class, and namespace scopes allow for it with clang.
static_assert(true, "");// namespace scope (good))
class X {
static_assert(true, "");// class scope (good))
[Code].....
I have made a datagrid in a WPF and added a button to add rows, here is the code for that:
this.itemListDataGrid.Items.Add(new TextBox());
Also, I have already got 3 colums in the datagrid pre-added by me, so when the rows are added I click on one to edit it and it comes up with error edit item not allowed.
Code:
#include "..ObjectsObjects.h"
class Idle;
class Objects;
class Goods;
[Code].....