I believe that everything is fine except that I can think of the condition can be inserted inside the parentheses ..
#include <iostream>
using namespace std;
int main() {
int i=0, k=0;
char *string_n, **matrix, temp;
[code].....
How can i change or add a cell to an array without knowing its length ? (I mean that I shouldn't know the length I need to make the length dynamic so i can add a cell)we just learned Dynamic assignment(I hope this is the correct name) and Pointers.
View 5 Replies View RelatedThis code snippet compiles and runs fine
Code:
#include <stdio.h>
int main(void) {
int i, a[i];
i=2;
for(int n=0; n<=i; n++)
a[n]=0;
[Code] .....
It prints out 3 "0", but when slightly changed
Code:
#include <stdio.h>
int main(void) {
int i, a[i];
i=200;
for(int n=0; n<=i; n++)
[Code] ....
It compiles fine but core dumps when run, how come? i'm using gcc version 4.4.7, and compiling like this
gcc -std=c99 test.c -o test
The WinAPI has a struct like this for raw input:
Code:
typedef struct tagRAWINPUT { RAWINPUTHEADER header;
union {
RAWMOUSE mouse;
RAWKEYBOARD keyboard;
RAWHID hid;
} data;
[code]...
The definition of the struct doesn't show it but the documentation says that bRawData is variable length. sizeof(RAWINPUT) will not be the correct size when the data field is of RAWHID type so how do you allocate a variable with automatic storage type that has the right size for the entire struct? You can get a header that has the size for the entire struct but how do you actually allocate storage space for the data without using malloc? I've seen some example code that used a char array but that violates aliasing rules and there are also alignment issues with that approach.
I want to ask for a number as an input during runtime and then create an 2-dimensional array of size as specified by user. i.e. if the user inputs 3, the array should be of size 3X3, and likewise...
View 9 Replies View RelatedFor my default constructor I need to set an array of strings to null and the size variable to 0. Here is my code for that
DynamicStringArray::DynamicStringArray() {
*DynamicArray[]=NULL;
size=0;
}
When I try and compile it I get an "expected primary expression before ']' token" error.
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <string>
#include <ctime>
using namespace std;
string randstr(int);
int main()
[Code]...
I want to generate random strings from A to Z with a specific length of 3 for each generation. For example:
BRC
YUG
YFH
How do I fufill this with the code presented and the function at the bottom?
I want to read a string of unknown length from stdin. I tried to follow the approach from this link.
[URL]....
My code is like this:
Code:
#include <iostream>
#include <string>
using namespace std;
int n;
cin >> n;
cout << "The value of n is " << n << endl;
string str;
getline(cin, str);
cout << "The entereed string is " << str << endl;
What I have noticed is that if I take integer input from cin (cin >> n in the above code before getline, the control does not stop on getline to take str as input from the console. If I don't do (cin >> n) before getline then the control stops on getline and takes the string as input.
What is the best way to read from console multiple strings of unknown length in combination with the integers?
How do you prompt the user to enter the number of elements for the array and use that information to creatr a variable length array? And then how do you prompt the user to enter in a number for each element of the array and scan in the appropriate numbers? the numbers are double precision floating point.
for example,
Enter the numbe of elements in the array: 3
Enter element 0: 3
Enter element 1: -1
Enter element 2: 4
I know it starts with
int main() {
double N;
int a[size];
printf("Enter the number of elements in the array:" );
scanf("%f", &size);
//I'm pretty sure this is wrong
I intend to reference this thread from another thread so I do not clutter that thread with code
/* This code is relied on by some of the functions I will post */
typedef unsigned long long zxumax;
typedef signed long long zxsmax;
[Code]....
I already have the standard one that mimics the one taught in schools written but I've found that there is a faster formula that can be used however I not sure how to implement this. The formula is called the "Fast Fourier Transform", any simplistic example using this function base:
typedef unsigned int uint;
typedef unsigned char uchr;
uint umul( uint* src, uint val ) {
uint des = *src;
[Code] ....
If you're doing the buffer based functions then I have some pre-made functions you may need. [URL]
On a controlled buffer of unsigned char it is possible to do subtraction faster than if you followed standard mathematical rules, here is an example:
typedef unsigned char uchr;
uchr num1 = 5; //00000101
uchr num2 = 3; //00000011
num2 = ~num2; // 11111100
++num2; // 11111101
uchr num3 = num1 + num2; // 00000010(2) - computer truncates result to fit char
Since you will be working with a buffer you don't even need to worry about truncating the final bit because the add function will not be able to reach it - unless it is given the ability to grow the buffer in which case you just set the bit to 0 yourself
What I'm trying to do is to assign the length of a string to an integer variable. This is what i tried, it did not work.
Code:
printf("Enter a string
");
fgets(test_pass, 30, stdin);
strcpy(x,(strlen(test_pass)));
printf("%d", x);
This was just a test, and it did not compile. How to do this?
I'm writing a program in which I have to use a matrix to represent a file in code. because it's a file, the size of the matrix is undefined, and therefore the matrix has to be dynamic. I found out that my compiler doesn't like dynamic multidimensional arrays, so I was thinking of this matrix as a dynamic (monodimensional) array of other dynamic (monodimensional) arrays. My program (and thus this example) uses unsigned chars.
unsigned char variable=something;
unsigned char**matrix=new unsigned char*[lenghtOfMainArray];
for(int rowNumber=0;rowNumber<lenghtOfArray;rowNumber++)
{
[Code].....
After i set the value in the first structure owners name, i set the cats name equal to it. but when i change the value in the first structure it doesn't change the value in the second structure.
So i need the dogs owners name to be equal to the cats owners name
So if i change the value of the dogs owner it also changes the value of the cats owner.
Code:
#include <stdio.h>#include <stdlib.h>
#include <string.h>
//stucture
struct structDog {
[Code] ....
I need to create dynamic string by given format(%d,%s,%f,%lf,%c) using variable number of arguments in function. This code gives me an error(main.exe has stopped working):
Code:
#include<stdio.h>
#include<stdarg.h>
#include<string.h>
#include<stdlib.h>
char *form(char *format,...);
char *form(char *format,...)
[Code]...
I assume the error is in functions(itoa,fcvt,ecvt).
I need to create dynamic string by given format(%d,%s,%f,%lf,%c) using variable number of arguments in function. This code gives me an error(main.exe has stopped working):
#include<stdio.h>
#include<stdarg.h>
#include<string.h>
#include<stdlib.h>
char *form(char *format,...);
char *form(char *format,...)
[Code] ....
I assume the error is in functions(itoa,fcvt,ecvt).
How to swap two strings without using 3rd variable? could it be done using constructors? If yes how?
View 11 Replies View RelatedI created a class (let call it X) which contains the structure to store the data from my data base. Them I have a class (call Y) which will contain a list for each row in my data base. Third, I have a class with thousands variables (Z). What I am trying to do is to take the list of objects (Y) that contains the data to initialize Z. What I want to now if I can do something like that.
Imaging that one of my rows contain the following data:
Type Nameofvariable etc...
"static const double; MNFAIL ; 0; 0; 0,25"
In my list I have a node with contain this data
I want to use the field Nameofvariable to initialize the variable called MNFAIL contained in my class Z.
Is it possible in C++
How I can implement it.
Tickable.h
#include <list>
#ifdef TICKABLE_EXPORTS //Automatically defined by MSVS
#define DLL __declspec(dllexport)
#else
#define DLL __declspec(dllimport)
#pragma comment(lib, "Tickable.lib")
#endif
class DLL Tickable{
[Code] ....
error LNK2001:
unresolved external symbol "private: static class std::list<class Tickable*,SKIPPED BITS> Tickable::subs" HUGE_SYMBOL_LIST
PATHTickable.obj
I know with such a tiny and insignificant class the dll export seems pointless but this class is actually intended to be a .lib ONLY. But it is derived from by .dll style classes, and through inheritance this error is the exact same as what appears in the derived class, I just imagine that the cut down version would be easier to work with.
Is it possible to hold either a static variable in a dll which is of a dynamic type, OR would it be possible to reference an external variable which is static throughout the instances and this variable can be chucked away in a namespace of mine somewhere?
I suppose my only other option (if this is possible) would be to define a maximum instance number and create a standard array of pointers but this could both waste so much memory when not in use and cause problems if I need more memory.
Is this possible in c++:
Code:
string s = R"(some rand string)" + argv[4] + R"(some rand string1)";
if it isn't, what is the best way to do this?
I'm working with arrays that might have NULL bytes in them and I'm wondering how to determine the length of the array or store it somewhere with the array (strlen() won't work because of the NULL, right?).
I've found advice like store the length of the array in the first byte of the array, but since sizeof(size_t) is 8 should I leave the first 8 bytes for the length?
Would it be better do define my own structure which would store the array and its length? What's the usual way these things are handled in practice?
I was reading in a book I had about C that an array has at the very end a "null character" signifying the end of the string inside it, "/o". So that made me think, "I guess one needs to declare arrays as having 1 extra space than one expects the array to need. I wonder what will happen if I exceed the array length?" So I made a program to test it out. Here is the program/results:
Code:
#include <stdio.h>
int main(void){
char name[3];
printf("
What's your name?
");
scanf("%s", name);
}
[code]....
As you can see my name was able to fit in the array somehow even though I only allocated 3 bytes to the array. I tried again using my legal first name, Benjamin, and it was still able to fit. How is the array able to hold my name when I declared it as only having 3 bytes?
i having a code to pass in array as argument, but the length returned is 1. This is not match with the array size.
int Getsize(int Array[])
{
int len = sizeof(Array)/sizeof(int);
cout << len << "
";
}
int main()
{
int X[] = {45, 12, 54, 83, 41, 36};
getsize(X);
}
I can't find any method of retrieving the length of an array except for doing this:
string first[] = {"a","be","see"};
int length = sizeof(first)/sizeof(first[0])
This is a very unconventional way of getting the length of an array.
first->length() would return 1 because it returns the number of letters in the first element of the array (which actually makes no logical sense).
first.size() would return 1 aswell as it's practically the same thing.
Since getting the length of an array is such a fundamental feat, how come I can't find a decent method of doing it?
Is there no buildt in method for this? If there is not, why has it not been implemented in the std?
I have a program with the following code, and I need to be able to either change the value of any or all of the strlen or to replace one or all with a temp array value. All values of the expression are arrays.
if (::strlen(tc_buf) + ::strlen(maxtime_buf) + ::strlen(" ") < sizeof(localBuf))