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Filling char pointer correctly


Filling char pointer correctly

By : ivan auchynnikau
Date : October 24 2020, 06:10 AM
I hope this helps you . I have a char pointer: , This sequence of statements
code :
char* s = new char[150];
s="abcdef";
char* s = new char[150];
std::strcpy( s, "abcdef" );
const size_t N = 150;
char* s = new char[N];
std::strncpy( s, "abcdef", N );
s[N-1] = '\0';
#include <iostream>
#include <cstring>

int main()
{
    const size_t N = 150;
    char *s = new char[N]{ '\0' };

    std::strncpy( s, "abcdef", N - 1 );

    std::cout << s << '\n';

    delete []s;
}
std::string s( "abcdef" );
std::string s;
s.assign( "abcdef" );


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istream::read not filling char array correctly

istream::read not filling char array correctly


By : Justin Tong
Date : March 29 2020, 07:55 AM
it should still fix some issue If you're reading in binary data then it's possible that you're reading a byte with a value of zero, or a null character in string terminology.
The way strlen() calculates the size of a string is by starting at the beginning of the string, and counting until it reaches a null character.
Filling a char pointer in a struct

Filling a char pointer in a struct


By : Ihza Bazabazie
Date : March 29 2020, 07:55 AM
I hope this helps you . I have defined a "car" struct with a model (char *model) and the year of the model (int year). I have a function that will create a new car struct; however, it is seg faulting when copying the char pointers. This is supposed to create a new node for a linked list. , For future reference this function fixed my issue...
code :
Car *createCar(char *model, int year){
    Car *new = malloc(sizeof(Car));
    new->year = year;
    new->model = malloc(strlen(model)+1);
    strcpy(new->model, model);
    new->next = NULL;
    return new;
}
Correctly pass a char array and char pointer to function by reference in C

Correctly pass a char array and char pointer to function by reference in C


By : Federico Gioia
Date : March 29 2020, 07:55 AM
hop of those help? There is no such thing as pass by reference in C. Everything in C is passed by value. This leads to the solution you need; add another level of indirection.
However, your code has other problems. You don't need to pass a pointer to pointer (or pointer to array) because you are not mutating the input, only what it refers to. You want to copy a string. Great. All you need for that is a pointer to char initialized to point to a sufficient amount of memory.
code :
int mutate(char **input) 
{
    assert(input);
    *input = malloc(some_size);
}

int main(void)
{
    /* p is an uninitialized pointer */
    char *p;
    mutate(&p);
    /* p now points to a valid chunk of memory */
    free(p);
    return 0;
}
How do I correctly work with char pointer to array in C++?

How do I correctly work with char pointer to array in C++?


By : CodeAndroid
Date : March 29 2020, 07:55 AM
Hope that helps I am trying to pick up my C++; I have basic understanding of pointers and references; but when it comes to char pointer to array, it seems nothing works for me. ,
// 1 this is a char pointer to a char;
code :
char * strr = "morning";
char * strr = "morning";
strr[0] = 'w'; // change to "worning"
const char * strr = "morning";
C char pointer, char pointer copying char pointer. Whether it can be considered as a automatic / dynamic space creation

C char pointer, char pointer copying char pointer. Whether it can be considered as a automatic / dynamic space creation


By : Greg Bouten
Date : March 29 2020, 07:55 AM
With these it helps In both char strB[20]; and uninitialized char * strB, you'll face Undefined behaviour.
In the former case, you'll be writing past allocated memory.
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