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Free () function in C

The void free function (void * ptr) frees the previously allocated memory by a call to calloc, malloc, or realloc

Declare the free () function in C

Below is the declaration for free () in C:

 void free ( void * ptr )

Parameters

ptr : This is the pointer to the previously allocated memory block with malloc, calloc or realloc to be freed. If the input parameter is a null pointer, no action will take place.

Returns the value

This function does not return any values.

For example

The following C program illustrates the usage of free () in C:

 #include #include #include int main () { char * str ; /* lan cap phat bo nho ban bau */ str = ( char *) malloc ( 15 ); strcpy ( str , "QTMTeam" ); printf ( "Chuoi = %s, tai Dia chi = %un" , str , str ); /* tai cap phat lai bo nho */ str = ( char *) realloc ( str , 25 ); strcat ( str , ".@gmail.com" ); printf ( "Chuoi = %s, tai Dia chi = %un" , str , str ); /* Giai phong bo nho da cap phat */ free ( str ); return ( 0 ); }

Compile and run the above C program to see the results.

According to Tutorialspoint

Previous lesson: calloc () function in C

Next lesson: malloc () function in C

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Programming C