C++ :: Char Array Reversing Function Using Pointer?
Feb 4, 2014Why does this code doesnt work?
#include <iostream>
#include <cstring>
#include <string>
using namespace std;
class my_string {
char* ptr;
[code] ....
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C/C++ :: Reversing A String / Char Array
Aug 12, 2013I'm new in the C programming language, so I tried to create a program that reverses a string. This is my code:
/* Reverse string */
#include <stdio.h>
#include <string.h>
int main() {
char s[8]="Welcome";
[Code] ....
The output of the program is "@".
C++ :: Pass A Pointer Into Function - Value Of Char?
Jan 2, 2014I'm having a problem understanding something with pointers. I was trying to pass a pointer into a function in MSVC-2013, like
char* charptr;
and then calling
myfunct(charptr);
and then inside the function i would set charptr equal to another char ptr, simply like
charptr = anothercharptr;
But this actually caused a compile failure in MSVC, saying charptr is being used without being initialized. in Code::Blocks it just gives buggy output.
I solved this issue by calling the function like
myfunct(&charptr);
and declaring the function like
myfunct(char**);
and then I had to dereference the charptr in the function when assigning it to another ptr, so
*charptr = anothercharptr;
It seems like you should be able to just pass a ptr into a function and change its address to that of another pointer? My main question is really, what is the value of a pointer? I thought the value of a pointer was just the memory address it contains. But then I had to reference it to pass it into the function.
What is the difference between the value of the char* charptr written as either charptr and &charptr?
C++ :: Using API Function That Has Char Pointer As Argument
Feb 5, 2014I am using a small robotic-car that is controlled by writing C/C++ codes under Linux. I need to use a particular function from the library provided by the manufacturer. The relevant API documentation for the function is:
BASEBOARD_ERROR_KIND ZMP zrc :: :: :: Baseboard GetRS232Data (char * msg )
RS232 data acquisition.
Argument:
[Out] msg Address of the acquired data.
Returns:
BASE_OK RS232 data acquisition success
BASE_BASE_232_GETDATA_ERR RS232 data acquisition failure
I have trouble writing the relevant code in the main program that invokes this function. Here is a snippet of what I have tried:
# include "Baseboard.h"
int main () {
Baseboard _Baseboard; // Class name is Baseboard
char *msg ;
[Code] ......
The part where I am uncertain is how to handle the char pointer "msg" in the declaration, function call and referencing. According to the documentation, the char pointer "msg" is the output of the function so I presume that is is somehow dynamically allocated. Am I handling the char pointer properly in the declaration, function call and referencing parts?
Another related question I have is: I am printing out the value of the variable "dummy". I always get 0 for it. Since the variable "dummy" is an enum of type BASEBOARD_ERROR_KIND which can take on two values (first value represents success and the second failure), it is alright to get a integer value of 0 for it if the function call was successful ? (I do not have much experience with using enums so this is a enum-related question on whether we can get an integer value representing the first enum value) .
C++ :: Using A Pointer To Char Array
Aug 31, 2013I like to use a Pointer to char array. And then I would like to do a Pointer Arithmetic by incrementing the Pointer. Finally I would like to see the Addresses of the Pointer to each of the char Array Elements. I had created a program below, but I am not getting any Addresses from my Pointer.
#include <iostream>
using namespace std;
int main () {
int ArraySize;
char ch[]= "This is a Char Pointer";
char* iPtr = ch;
[Code] ....
C :: Pointer To A Char Inside Array
Jun 7, 2013Alright, so I have a code that's not giving me errors, but it doesn't seem to retain what I put into an array. Not sure If I'm missing something...
Code:
#include <stdio.h>
int main (void)
{
const char *pointer;
const char alphabet[] = "ABCDEFG";
pointer = &alphabet[5];
printf("pointing to %c of the alphabet
", pointer);
return 0;
}
Trying to get my pointer to return the letter in the [5] spot or "F". Not receiving any errors when compiling, but I seem to get different answers every time I run it.
C :: How To Assign Values To Pointer Char Array
Aug 10, 2013I can assign values to pointer character array like this...
Code:
char *array[4]={"abc","xyz","dgf","sdt"} ;
but the case is i don't know how to assign strings through key board ???? with using gets ,getchar or other suitable function
C :: Array Of Char Pointer Type Mismatch
Apr 20, 2013I have an array of char pointers:
Code: char *input_args[MAX_ARGS];
And I have this function:
Code: BOOL parseArgs(char **input_args[], input arg_num);
I am trying to pass a pointer to this char pointer array like this:
Code: parseArgs(&input_args, args_num);
But the compiler is complaining:
Code: warning: passing argument 1 of 'parseArgs' from incompatible pointer type ...
note: expected 'char ***' but argument is of type 'char * (*)[20]'
Tried a bunch of stuff but nothing works.
C++ :: Initialize Char Pointer Array In Struct
Nov 28, 2014I am trying to store data in a struct to be able to read it latter . have problems initializing this.
struct FoodAndDrink {
struct Food {
char* CannedGoods[2] = {
"Canned Spaghetti",
"Canned Tuna",
[code] .....
C++ :: Size Of Char Array - Comparing Name To Another One (Pointer)
Jul 13, 2013I have function that looks like this myfoo(char* Name) Now i want to compare this name to another one . But the another name is a pointer . This my code :
bool Tribe::RemoveSurvavior(char *H_Name) {
const char *p;
p=SurpointArr[i]->GetSurvivor_Name();
}
I need to compare if p is same as H_Name.
Mine is do it with for on each element but when i use sizeof it gives me size of char and not real size of the name.
C :: How To Stop Passing Char Array Index As Pointer
Dec 23, 2013I am trying to write a light weight printf style function.
I have got this far:
Code:
void println(const char *txData){
LOG(__PRETTY_FUNCTION__);
UARTPuts (LPC_UART0, txData);
}
void miniPrint(const char *format, ...)
{
unsigned int index = 0;
va_list argptr;
va_start(argptr, format);
[Code]....
I understand why I think. When I am passing the reference to the array possion it is outputting everything up to the next /0. So my question is how do I stop it?
I dont have much choice as to how the output wants it:
Code: void UARTPuts(LPC_UART_TypeDef *UARTx, const void *str)
Thats library code, so I dont want to change it. I.e I have to pass an address into println.
C++ :: Why Cannot Copy String Pointed By Pointer To Array Of Char
Feb 22, 2013I have this function in a class: and a private declaration: how can I copy the parameter "ProductName" to allowedProductName. I tried all combination and I can't get it to compile.
private:
StatusPanel &statusPanel;
char allowedProductName[MAX_NAME_LENGTH];
[Code].....
C++ :: Wrong Return Type When Returning Char Array As Pointer
Apr 25, 2014I am writing a class Player which has several char arrays as private fields. I am trying to write a method which returns an array as a pointer, but doesn't alter the array in any way, thus the const.
Here is a snippet:
Code: class Player
{
private:
char state[MAX_STATE_CHAR + ONE_VALUE];
int rating;
char last[MAX_NAME_CHAR + ONE_VALUE];
char first[MAX_NAME_CHAR + ONE_VALUE];
int groupNumber = NEG_ONE;
public:
char * GetFirst() const
{
return first;
}
Visual studio is saying that the return type doesn't match.
C :: Reversing Elements In Array
Apr 15, 2014Write the definition of a function reverse , whose first parameter is an array of integers and whose second parameter is the number of elements in thearray . The function reverses the elements of the array . The function does not return a value .
Code:
void reverse(int a[], int num) {
for ( int i=0; i <= num/2 ; i++){
int temp = a[i];
a[i] = a[num-i-1];
a[num-i-1] = temp;
} }
This is supposed to be the answer but I'm not quite sure why this is. I understand everything up until the actual loop. For one, shouldn't "int i" be declared outside the loop (I thought perhaps this was an error in the solutions)?
The main thing that I do not understand is the conditional statement.
Code: i<=num/2;
I don't understand why the "num/2" is necessary here. Also I can't really remember but is there a command that actually reverses an array?
C/C++ :: Reversing Array Contents
Feb 21, 2015I'm trying to reverse 25 items that are in my array by using a For Loop and sending 2 of the numbers to a function at a time. The code I have right here, is not working at the moment, I cannot find the problem because i've been staring at my code for too long.
int farEnd = 24;
for (int i = 0; i < 24; i++){
Swap(intArray[i], intArray[farEnd]);
farEnd--;
}
Also here is the code in my function
void Swap(int num1, int num2){
int temp = 0;
temp = num1;
num1 = num2;
num2 = temp;
}
Visual C++ :: Backward Function - Reversing Words Entered?
Apr 21, 2013My program , it says there is no problem with the build but when exe. it displays a bunch of backward 'k' instead of reversing the words entered.
Problem: Enter in a C-string and use function to display the word backward. (it might work with a pointer but I am not sure how to go about it)
lab10_p2.cpp
C/C++ :: Reading A File Into Array Then Reversing The Array
Jan 19, 2015This is what I am supposed to be doing with this problem: Read the integer values in the file "numbers.dat" and display
* them in reverse order (that is, display the last number in the
* file first, the second-to-last second and so on). Use an array to
* store the values. It is safe to assume that the file contains no
* more than 100 values.
I have gotten far enough to read the file and display as an array, but it is displaying vertically rather than horizontally. So it is displaying 10 and a 1 on the first line then the 0 on the second line. Before I can work the reverse part out, I need it to display each number as 10 line 1 -235 line 2 so on and so forth.
This is my code so far:
void display_array_reversed() {
ifstream fin ("numbers.dat");
if (!fin){
cerr << "Error opening file" << endl;
exit(1);
[Code] .....
C :: Returning Char Array By Function
Mar 2, 2015I'm having trouble returning a char array by a function, here's the code. The problem is the 'reverse' function, the purpose of the function is to send two char arrays, 'newline' containing the char array, reverse it and place it in the 'rev' char array then output it back in main, however the output remains blank so I assume there must be something wrong with the reverse function.
Code:
#include <stdio.h>
#define MAXLINE 10
int fgetline(char line[], int maxline);
void copy(char to[], char from[]);
void reverse(char forw[], char rev[], int arrsize);
[Code] .....
C :: Getting Const Char Array From Function
Jun 7, 2013Now I am stuck with getting const char* array from function to main.
Code:
const char* values[3];
strings_to_array()
printf("%s
", values[1]);
printf("%s
", values[2]); function: Code:
const char* strings_to_array()
}
[code]....
First, I cant get strings printed out in main.
Second, is here way to get number of such elements which array contains like higher languages have "count" or "ubound" or such?
Third, next function which need that array assumes that array of const chars* is 1 based. Can that be set in C or here are allways zero based arrays?
C++ :: Passing Char Array To Function
Nov 23, 2013In the below program, When the getline function is called, it passes a char array of size 1000 by VALUE. It must have passed by value because there is no pointer or reference in the argument list of the getline function definition. And if that's the case, when exiting the getline function, isn't the s[] char array destroyed? And if it is destroyed, then when we reference line in the copy function, what are we actually copying?
#include <stdio.h>
#define MAXLINE 1000/* maximum input line length */
int getline(char line[], int maxline);
void copy(char to[], char from[]);
/* print the longest input line */
main() {
[Code] .....
C++ :: Returning Char Array To Main Function
May 15, 2014I want to return a char array to the main() function, but its returning garbage value.
#include<stdio.h>
//#include<conio.h>
#include<string.h>
char* strtrmm();
int main() {
char str1[100],c1[100];
[Code] .....
C :: Passing Array Of Pointer To A Function
Sep 7, 2013Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_CMD_LINE 500
void tokenize(char *cmd_ln, char *fun_tknzd[], int *argument_cnt);
[Code] ....
I am trying to pass the value of fun_tknzd to str_tknzd
C++ :: Returning A Pointer To 2D Array From A Function
Dec 10, 2014I know how to pass a 2-D array to a function. The prototype for that is void f(int (*p)[2]) assuming the array is of integers and there are 2 columns in it.
However, if I wanted the same function to return a pointer to a 2-D array, what would be the prototype?
C++ :: Passing Array As Pointer To A Function?
Apr 24, 2014I can clearly understand how to pass a dynamic array to a function and modified within the function..
My aim is to get back the array initialized as I am trying on the next sample of code..
Code:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <iostream>
#include <fstream>
using namespace std;
#define N3//number of bodies
void initialise( double *M[], double *X[], double *y[])
[code]....
C :: Function Which Finds Largest Contiguous Values Of Char In 2D Array
Nov 5, 2013I am required to write a program which, when given an nxn 2D array of char, and the specified coordinates of a specific point in that array, returns thelargest number of horizontal, vertical or diagonal contiguous (side-by-side) sequence of points of that same char value that intersects with the given point.
The way I took on this problem was to:
1) First find out the number of points with the same char value up, down, right, left, north-east, north-west, south-east, and south-west of the given point.
2)Add up+down+1(the one is for the point itself), north-west+south-east+1, etc...
3) Finally I compared the four values (updown, rightleft, NESW, NWSE) and returned the largest one.
Well, that's how the program is supposed to work in theory but as you can probably guess it doesn't work. In addition to telling me what I'm doing wrong, is there a simpler way to do what I am trying to accomplish?
Here's the code:
Code:
int findLongest(char **board, int n, int row, int col)
{
char current;
int rightleft, updown, NESW, NWSE;
int r, c, c1=0, c2=0, c3=0, c4=0, c5=0, c6=0, c7=0, c8=0, d;
int t1=1, t2=1, t3=1, t4=1, t5=1, t6=1, t7=1, t8=1;
current=board[row][col];
//check Above: col remains the same
for(r=row-1;r>=0||t1!=0;r--)
//with the condition r>=0 I made sure not to accidentally check values outside of the array
[Code]...
C++ :: Function To Change Char Array String To Lower Case
Feb 17, 2014This code ran well until i added in the ToLower function which is supposed to convert the char array string to lower case (based off ascii strategy -32). correct this function so it converts string to lower case and doesn't get errors.
#include <iostream>
#include <string>
using namespace std;
const int MAX = 81; //max char is sting is 80
void ToLower(char s[]);
int main(){
string y_n;
[Code]...