#include <stdlib.h></p> <p>void *malloc(size_t size);</p> <p>void exemple(void)<br /> {<br /> char *string;</p> <p> string = malloc(sizeof(char) * 5);<br /> if (string == NULL)<br /> return;<br /> string[0] = ‘H’;<br /> string[1] = ‘e’;<br /> string[2] = ‘y’;<br /> string[3] = ‘!’;<br /> string[4] = ‘\0’;<br /> printf(“%s\n”, string);<br /> free(string);<br /> }</p> <p>/// output : “Hey!”

<stdlib.h>

#include <stdlib.h><br /> int main(){<br /> int *ptr;<br /> ptr = malloc(15 * sizeof(*ptr)); /* a block of 15 integers */<br /> if (ptr != NULL) {<br /> *(ptr + 5) = 480; /* assign 480 to sixth integer */<br /> printf(“Value of the 6th integer is %d”,*(ptr + 5));<br /> }<br /> }

int* a =(int*)malloc(sizeof(int))

Example: ptr = (int *) malloc (50)

// Let’s allocate enough space on the heap for an array storing 4 ints</p> <p>intArray = (int *) malloc(4 * sizeof(int)); // A pointer to an array of ints</p> <p>intArray[0] = 10;<br /> intArray[1] = 20;<br /> intArray[2] = 25;<br /> intArray[3] = 35;

// if you initialize a pointer and want to use it like an array,<br /> // you have to claim the space you use,<br /> // that is what the memory-allocation-funtion (malloc) does;</p> <p>// exaple for that: str(0) belongs to you, but str(1), str(2), … do not<br /> // if you do not use the malloc funtion;<br /> // you can access it, but it could be used by another programm;</p> <p>#include <stdio.h><br /> #include <stdlib.h></p> <p>void func(void)<br /> {<br /> char *str = malloc(sizeof(char) * 5); // sizeof –> char needs<br /> // a specific space per value saved;<br /> // *5 –> 5 is the number of values in the array;</p> <p> char *str1 = malloc( 5 * sizeof *str1 );// |<br /> char *str2 = malloc( sizeof(char[5]) );// | other syntaxes</p> <p> if(str == NULL) { exit(1); } // malloc returns NULL<br /> // if it could not allocate the memory;<br /> str[0] = ‘H’;<br /> *(str+1) = ‘e’; // used like pointer<br /> str[2] = ‘y’; // used like array<br /> *(str+3) = ‘!’;<br /> str[4] = ‘\0’;</p> <p> printf(“%s\n”, str);</p> <p> free(str); // frees the memory allocated to str;<br /> // if you free the memory too early and try to access str later<br /> // that is called a memory leak;<br /> }</p> <p>int main(void)<br /> {<br /> func();<br /> return 0;<br /> }</p> <p>// shell: Hey!</p> <p>// improved version of Thurger’s

int main(int argc, char *argv[])<br /> {<br /> int* memoireAllouee = NULL;</p> <p> memoireAllouee = malloc(sizeof(int));<br /> if (memoireAllouee == NULL) // Si l’allocation a échoué<br /> {<br /> exit(0); // On arrête immédiatement le programme<br /> }</p> <p> // On peut continuer le programme normalement sinon</p> <p> return 0;<br /> }<br />

/*<br /> *Dynamic memory creation using malloc<br /> *Language: C<br /> */</p> <p>#include<stdio.h><br /> //To use malloc function in our program<br /> #include<stdlib.h></p> <p>int main()<br /> {<br /> int *ptr;</p> <p> //allocating memory for 1 integer<br /> ptr = malloc(sizeof(int));</p> <p> if(ptr != NULL)<br /> printf(“Memory created successfully\n”);</p> <p> return 0;<br /> }

In C, the library function malloc is used to allocate a block of memory on the heap. The program accesses this block of memory via a pointer that malloc returns. When the memory is no longer needed, the pointer is passed to free which deallocates the memory so that it can be used for other purposes.