malloc in c
#include <stdlib.h>
void *malloc(size_t size);
void exemple(void)
{
char *string;
string = malloc(sizeof(char) * 5);
if (string == NULL)
return;
string[0] = 'H';
string[1] = 'e';
string[2] = 'y';
string[3] = '!';
string[4] = '\0';
printf("%s\n", string);
free(string);
}
/// output : "Hey!"malloc
// if you initialize a pointer and want to use it like an array,
// you have to claim the space you use,
// that is what the memory-allocation-funtion (malloc) does;
// exaple for that: str(0) belongs to you, but str(1), str(2), ... do not
// if you do not use the malloc funtion;
// you can access it, but it could be used by another programm;
#include <stdio.h>
#include <stdlib.h>
void func(void)
{
char *str = malloc(sizeof(char) * 5); // sizeof --> char needs
// a specific space per value saved;
// *5 --> 5 is the number of values in the array;
char *str1 = malloc( 5 * sizeof *str1 );// |
char *str2 = malloc( sizeof(char[5]) );// | other syntaxes
if(str == NULL) { exit(1); } // malloc returns NULL
// if it could not allocate the memory;
str[0] = 'H';
*(str+1) = 'e'; // used like pointer
str[2] = 'y'; // used like array
*(str+3) = '!';
str[4] = '\0';
printf("%s\n", str);
free(str); // frees the memory allocated to str;
// if you free the memory too early and try to access str later
// that is called a memory leak;
}
int main(void)
{
func();
return 0;
}
// shell: Hey!
// improved version of Thurger'sCopyright © 2021 Codeinu
Forgot your account's password or having trouble logging into your Account? Don't worry, we'll help you to get back your account. Enter your email address and we'll send you a recovery link to reset your password. If you are experiencing problems resetting your password contact us
