c++,arrays,reference,char,swap , Swap and Return Char Array from the Function


Swap and Return Char Array from the Function

Question:

Tag: c++,arrays,reference,char,swap

I know there are many questions related to my this question but still facing problem. I'm using the function to swap array mean when I input ABCD it shoudl return DCBA. Code is below check where is problem. Is there a way to pass second empty array as reference? Swap is working fine, but array is not returning fine. I just want to solve this code related to [characters array]. Don't discuss about string etc.

#include <iostream>
#include <string.h>
#define MAX 80
using namespace std;
char* reversit(const char a[]){
    int size=strlen(a)-1;
    char b[MAX];
    int i;
    for(i=0; i<strlen(a); i++){
        b[size--] = a[i];
    }
    b[i]='\0';  
    return b;
}
int main(){

    char a[MAX];
    char b[MAX];
    cin.get(a,MAX);
    b=reversit(a);
    cout << b;
    return 0;
}

Answer:

First of all, you can indeed not return arrays. That's one big problem with them.

If you really want to use char[], you can just pass the output array as an extra parameter:

void reversit(const char *a, char *b){
    int size=strlen(a)-1;
    int i;
    for(i=0; i<strlen(a); i++){
        b[size--] = a[i];
    }
    b[i]='\0';  
}

Note that char[] and char* is the same as a function argument.


Related:


opencv window not refreshing at mouse callback


c++,opencv
I am trying to draw with mouse move in an opencv window. But when I draw, nothing draws on the window. When I try to close the window from the cross in the topleft(ubuntu), it opens a new window which it should be as I haven't pressed escape, and in...

Create array from another with specific indices


javascript,arrays
I have two arrays, one of data and one of indices: var data = [ 'h', 'e', 'l', 'l', 'o', ' ' ]; var indices = [ 4, 0, 5, 0, 1, 2, 2 ]; I would like to create a third array, using cells of data in order indicated...

Comparing arrays with numbers in vb.net


arrays,vb.net
I need a way to compare two arrays in vb.net and save result in third array: Dim KonRes(3) As Integer Dim UserRes(3) As Integer Dim YelRed(3) As Integer KonRes(0) = 1 KonRes(1) = 2 KonRes(2) = 3 KonRes(3) = 4 UserRes(0) = 4 UserRes(1) = 3 UserRes(2) = 2 UserRes(3)...

How to pivot array into another array in Ruby


arrays,ruby,csv
I have a multidimensional array like this one : myArray = [["Alaska","Rain","3"],["Alaska","Snow","4"],["Alabama","Snow","2"],["Alabama","Hail","1"]] I would like to end up with CSV output like this. State,Snow,Rain,Hail Alaska,4,3,nil Alabama,2,nil,1 I know that to get this outputted to CSV the way I want it I have to have output array like this: outputArray =[["State","Snow","Rain","Hail"],["Alaska",4,3,nil],["Alabama",2,nil,1]]...

accessing range of values in arduino array


arrays,arduino
I have data packet coming in like this in Arduino. Data: 12345678901234 I can access the 5th value using the code below. id = sx1272.packet_received.data[4]; My question is how do I access a rang of values? I tried this, but the colon throws an error. char[2] id; if( sx1272.packet_received.length >...

Merge and sum values and put them in an array


javascript,arrays,angularjs,foreach
I'm retrieving values from an external source and apply a foreach loop to the results, with the code below. angular.forEach(data, function(value, key) { if (value.start_date > firstdayOfWeek && value.start_date < lastdayOfWeek) { console.log(value.firstname + ' - ' + value.distance); } else { //do nothing } }); The result is console...

jQuery - Value in Function


jquery,arrays,function
My array: array.name = "Thiago"; array.date = "01/01/1990"; I want a function like this: function myFunc( array, fieldToCompare, valueToCompare ) { if( array.fieldToCompare == "Thiago" ) alert(true); } myFunc( myArray, name, "Thiago" ); is it possible?...

Issue when use two type-cast operators in template class


c++
I define a template class in which, I define two type-cast operator template <class base_t> struct subclass { base_t base; //any function which defined for 'base_t' can be used with 'subclass<base_t>' operator base_t&() { return base; } //I want 'subclass<base_t>' can be converted to any class which 'base_t' can //I...

How do I print more than one value per key in Tcl?


arrays,tcl
array set array_in_twos { set1 table set2 chair set1 chair } foreach combo [array names array_in_twos] { puts "$combo is $array_in_twos($combo)," } outputs: set1 is chair, set2 is chair, It seems the second 'set 1' replaces the first 'set 1'. how do i print all? set1 is table, set2 is...

do calculation inside JSONArray in Java


java,arrays,json
I have a simple issue but cannot solve it as I am not very good at algorithm! I have an JSONArray in this form: [{"values":[{"time":1434976493,"value":"50"}, {"time":1434976494,"value":"100"}],"counter":"counter1"}, {"values":[{"time":1434976493,"value":"200"}, {"time":1434976494,"value":"300"}],"counter":"counter2"}, {"values":[{"time":1434976493,"value":"400"}, {"time":1434976494,"value":"600"}],"counter":"total"}] What I want to do is to get the integer value for counter 1 and counter 2 and then divide...

Undefined behaviour or may be something with memset


c++,undefined-behavior
I was trying to save the binary equivalent of a 32 bit number in an array A. For testing my showbits() function , I choosed 8,9 when I came across this thing: I am facing an unreasonable thing in my code when I am placing memset in the function showbits(),I...

Incorrect Polar - Cartesian Coordinate Conversions. What does -0 Mean?


c++,polar-coordinates,cartesian-coordinates
I am getting incorrect conversions from polar to cartesian coordinates and vice versa. My code produces weird points like (1,-0). Im using this calculator to check my conversions. Also one of the conversions is completely wrong when I convert back to cartesian coordinates. Point b: (0,1) => (1,1.5708) => (0,0)...

Strings vs binary for storing variables inside the file format


c++,file,hdf5,dataformat
We aim at using HDF5 for our data format. HDF5 has been selected because it is a hierarchical filesystem-like cross-platform data format and it supports large amounts of data. The file will contain arrays and some parameters. The question is about how to store the parameters (which are not made...

Infinite loop with fread


c,arrays,loops,malloc,fread
I'm trying to allocate an array 64 bytes in size and then loop over the array indexes to put a read a byte each from the inputfile. but when I don't malloc() the array indexes, the loop stays in index0 (so each time it loops it replaces the content in...

C++ Isn't this a useless inline declaration?


c++,inline,private,member,protected
This is another question about inlining a function. But I will take possible comments and answers right away: Defining a function inside a class makes it inline automatically. The same behaviour can be achieved by marking a function with inline outside of the class. An inline function doesn't have to...

Having two arrays in variable php


php,mysql,arrays,variables,multidimensional-array
i've this code, i'm trying to explode my date e.g "04 June 2015" to have the day and the month in other 2 variables, but i have all in a method, with an array, is it possible, my code doesn't work, it writes "Array[0]" why? while ($i < $number) {...

How can I convert an int to a string in C++11 without using to_string or stoi?


c++,string,c++11,gcc
I know it sounds stupid, but I'm using MinGW32 on Windows7, and "to_string was not declared in this scope." It's an actual GCC Bug, and I've followed these instructions and they did not work. So, how can I convert an int to a string in C++11 without using to_string or...

OpenCV - Detection of moving object C++


c++,opencv
I am working on Traffic Surveillance System an OpenCv project, I need to detect moving cars and people. I am using background subtraction method to detect moving objects and thus drawing counters. I have a problem : When two car are moving on road closely them my system detects it...

pointer to pointer dynamic array in C++


c++,arrays,pointers
I've been having bad luck with dynamic pointers when I want to close it. why the application wrote to memory after end of heap buffer? how can I close my array? int main() { . . int **W; W = new int* [n]; for (int i=1; i <= n; i++)...

Same function with and without template


c++,c++11
I am trying to understand a piece of code of C++11. A class contains 2 functions as shown below: class abc { public: void integerA(int x); template<typename typ> void integerA(typ x); }; I am unable to understand benefit of declaring 2 same functions. Why not declare only one template function?...

Javascript function to validate contents of an array


javascript,arrays
Here's what is asked: validItems(items) – this function receives a string array of items which are to be for a customer. The function returns an empty string indicating all item codes in the array are valid; otherwise the function returns the first invalid item code in the array. All item...

Implicit use of initializer_list


c++,c++11,initializer-list
§[dcl.init.list] 8.5.4/2: The template std::initializer_list is not predefined; if the header <initializer_list> is not included prior to a use of std::initializer_list — even an implicit use in which the type is not named (7.1.6.4) — the program is ill-formed. Does that mean this program is ill-formed? #include <vector> int main()...

Ruby: How to copy the multidimensional array in new array?


ruby-on-rails,arrays,ruby,multidimensional-array
seating_arrangement [ [:first, :second, :none], [:first, :none, :second], [:second, :second, :first], ] I need to copy this array into new array. I tried to do it by following code: class Simulator @@current_state def initialize(seating_arrangement) @@current_state = seating_arrangement.dup end But whenever I am making any changes to seating_arrangement current_state changes automatically....

Marshal struct in struct from c# to c++


c#,c++,marshalling
I have the following structures in C# and C++. C++: struct TestA { char* iu; }; struct TestB { int cycle1; int cycle2; }; struct MainStruct { TestA test; TestB test2; }; C#: [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi, Pack = 1)] internal struct TestA { [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 36)] private string iu; public...

Translating a character array into a integer string in C++


c++,arrays,string
I was trying to achieve translating a character array into a integer string and corresponding character to their alphabetical order. For instance: A(a) = 0 , Z(z) = 25. string key_char = argv[1]; string key_num; for (int i = 0; i < key_char.length(); i++){ if (isalpha(key_char[i])){ if (islower(key_char[i])){ key_num[i] =...

Why are shaders and programs stored as integers in OpenGL?


c++,opengl,opengl-es,integer,shader
I'm following the "OpenGL Superbible" book and I can't help but notice that when we create a shader and create the program that we attach the shaders to, we store them as GLuint which are unsigned integers. Why are they stored as numbers? What does the value of the number...

undefined reference to `vtable for implementation' error


c++,build,makefile
I wrote some c++ files and after compiling with out make file it works fine . But when using make file it pop out some errors . My codes are : include directory files : application.h #ifndef APPLICATION_H #define APPLICATION_H #include "employee.h" #include "employee_data.h" #include "employee.h" ...some defintions here... #endif...

array and function php


php,arrays
I'm just a beginner in PHP coding. I've been reading through a tutorial, but having some trouble with basic PHP concepts. If you could help me, I'd be much obliged. I'm having trouble understanding why the following code doesn't work. <?php function sum($x, $y) { $z = $x + $y;...

Get an ordered list of files in a folder


c++,boost,boost-filesystem
I have used boost::filesystem::directory_iterator in order to get a list of all the available files into a given folder. The problem is that I supposed this method would give me the files in alphabetical order, while the results seem pretty random. Is there any fancy way of alphabetically sorting them?...

3 X 3 magic square recursively


c++,algorithm,math,recursion
I'm trying to find all possible solutions to the 3X3 magic square. There should be exactly 8 solutions. My code gets them all but there are a lot of repeats. I'm having a hard time tracking the recursive steps to see why I'm getting all the repeats. // This program...

Type function that returns a tuple of chosen types


c++,templates,c++11,metaprogramming
I've implemented a type function Tuple that turn a list of My_enum values into an std::tuple of corresponding types: #include <tuple> enum My_enum{ t_int, t_double }; // Bind_type is a type function that given a My_enum returns the corresponding type template<My_enum E> struct Bind_type; template<> struct Bind_type<t_int>{ using type =...

Javascript sort array of objects in reverse chronological order


javascript,arrays,sorting
I have an array of objects which holds a list of jobs and I would like to sort them in reverse chronological order as they would appear on a resume for example. I came up with the below solution which 'seems' to work but I was wondering if there is...

C++ template template


c++,templates
I'm trying to understand C++ template templates by implementing a generic container class. Here is the code: using namespace std; template <typename T, template <typename STORETYPE> class Container> class Store { public: ~Store() {}; Store() {}; void someFunc( const T & ) {}; //... private: Container<T> storage; }; int main(int...

Substring of a file


javascript,arrays,substring
I have a file that is structure like this : var file = "a|b|c|d, a|b|c|d, a|b|c|d, a|b|c|d, a|b|c|d"; Now I would extract all letters "c" and "d" of this file and put those letter in array, structure like this: var array = [ [a,b,1], [a,b,2], [a,b,3], [a,b,4], [a,b,5] ]; How...

.cpp:23: error: cannot convert ‘std::string’ to ‘const char*’ for argument ‘1’ to ‘int atoi(const char*)’


c++,string
Here a basic code I'm trying to run But I'm having trouble with stoi (it's c++) I keep getting error: ‘stoi’ was not declared in this scope I tried atoi and strtol with this error .cpp:23: error: cannot convert ‘std::string’ to ‘const char*’ for argument ‘1’ to ‘int atoi(const char*)’...

Blank screen on GridView


android,arrays,gridview
I'm trying to create a GridView with an array of strings. These are XML, and MainActivity and Adapter, but what I get is a blank screen. I'm change the background, but the result is the same, but clicking on a point on the screen appears to me the toast stating...

dispatch response packet according to packet sequence id


c++,boost,boost-asio
I have a third-part server, and I'm writing a dll interface for it, my clients use my dll to communicate with the server. The protocol uses a long tcp connection, all traffic goes from this tcp connection. There could be sending/receiving multiple packets at the same time, like a send_msg...

Get elements containing text from array


javascript,jquery,html,arrays,contains
I want to search all the elements containing any string in the array. For example I have following list of items <ul> <li>cricket bat</li> <li>tennis ball</li> <li>golf ball</li> <li>hockey stick</li> </ul> and this array var arr = ['bat', 'ball']; It should select all the elements having text bat and ball....

How to innerHTML a function with array as parameter?


javascript,arrays,loops,foreach,innerhtml
I am learning about looping thorugh arrays - I want to pass the result of an if else statement in the forEach function (inside another function with array as parameter) to HTML using innerHTML (does not have to be innerHTML if you know better methods I do not mind). It...

Method returning std::vector>


c++
As a continuation of a: Thread, I came across a problem with writing a method of a class which returns: std::vector<std::unique_ptr<Object>> I get compiler errors when such a return type is written. There is some problem with delete operand or something ... Generally, I've wanted to write a method which...

How to pass array in rails 4 strong parameters


ruby-on-rails,arrays
I have to pass a array of food_item_ids in my order_controller. Every order will have many food_items. How can I pass these food_items_id as an array in strong parameters. orders_controller.rb def create @order = Order.new(order_params) if @order.save render :json, @order, status:201, location: [:api, @order] else render :json, { errors: @order.errors...

How can I access the members of a subclass from a superclass with a different constructor?


c++,inheritance,constructor,subclass,superclass
I have the following class and typedef: class Object { protected: long int id; public: Object(void); ~Object(void) {}; long int get_id(void); }; typedef map<string, Object> obj_map; And then I have its child: class Image: public Object { private: path full_path; int x; int y; img image; public: Image(path p, int...

C++11 Allocation Requirement on Strings


c++,string,c++11,memory,standards
I had heard that C++11 was going to require strings to be allocated in contiguous memory. I even thought I saw a stack overflow question on it, but I can't seem to find it. I know that in practice both gcc and Visual Studio do allocate strings contiguously, I'm just...

How can I tell clang-format to follow this convention?


c++,clang-format
I would like to have this: if (!enabled) { return; } turned to this: if (!enabled) { return; } (In other words, I want short if-statements on a single line but keep the {} around them) Currently I'm using the following configuration: AllowShortIfStatementsOnASingleLine: true AllowShortLoopsOnASingleLine: true AllowShortCaseLabelsOnASingleLine: true AllowShortFunctionsOnASingleLine: true...

Notice: Array to string conversion in “path of php file” on line 64


php,mysql,arrays,oracle
PHP CODE -: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Untitled Document</title> </head> <body> <?php $rows =0; $fp = fopen("leave1.csv","r"); if($fp){ while(!feof($fp)){ $content = fgets($fp); if($content) $rows++; } } fclose($fp); //echo $rows; $_SESSION['rows'] = $rows; ?>...

Add more features to stack container


c++,visual-c++,stl
I am using default features(push, pop, top, empty, size) of stack container of STL. If I want to add more features like access an element from middle of stack. How could I do this? Thanks...

Validate case pattern (isupper/islower) on user input string


c++,user-input
I need to write a program that checks if the user-provided first and last names are correctly typed. The program needs to validate that only the first letter of each name part is uppercase. I managed to write code that checks the first character of the input. So I have...

create vector of objects on the stack ? (c++)


c++,vector,heap-memory
I am creating a temporary vector of pointers to myObject objects. But I am wondering about what happens to the objects I created... { std::vector<myObject *> myVector; myVector.reserve(5); for (int i = 0 ; i < 5 ; ++i){ myVector[i] = new myObject(); } } I assume that at the...