[C Language] Data Structure-preparation knowledge cross-Function Memory, data structure preparation

[C Language] Data Structure-preparation knowledge cross-Function Memory, data structure preparation

Memory usage across functions
When a function stops running, the memory allocated by the malloc function will not be released if free is not called.
You can continue to use this function in another function.

 

#include <stdio.h>
#include <malloc.h>
// Use memory across functions
// Pass the structure pointer, occupy less memory
struct Student {
         int age;
         int score;
         char * name;
};
struct Student * createStudent (struct Student *); // Front declaration
void showStudent (struct Student *);
int main (void) {
         struct Student * pst; // Definition, currently only 4 bytes
         pst = createStudent (pst); // Create, allocate memory
         showStudent (pst); // Show, continue to use the above memory
}
struct Student * createStudent (struct Student * pst) {
         pst = (struct Student *) malloc (sizeof (struct Student)); // Allocate memory to this structure and return a pointer
         pst-> age = 100; // structure member assignment
         pst-> score = 9999;
         pst-> name = "taoshihan";
         return pst;
}
void showStudent (struct Student * pst) {
         // Continue to use the memory allocated in the above function
         printf ("% s ===% d ===% d", pst-> name, pst-> age, pst-> score);
}