sorting C structs, an example

main.c

 typedef struct stump {
    char * name;
    int data;
 } stump;
 
 typedef struct container {
    stump ** node_array;
 } container;
 
 int compare_stumps(const void *a, const void *b) {
    stump *ia = (stump *)a;
    stump *ib = (stump *)b;
    return (int)(ia->data - ib->data);
 }
 
 int main(int argc, char **argv) {
     container *c = malloc(sizeof(container *));
     c->node_array = calloc(2, sizeof(stump *));
     
     stump *one = malloc(sizeof(stump *));
     stump *two = malloc(sizeof(stump *));
     one->name = "a";
     one->data = 1;
     
     two->name = "b";
     two->data = 2;
     
     c->node_array[0] = two;
     c->node_array[1] = one;
     
     qsort(c->node_array, 2, sizeof(stump *), compare_stumps);
     printf("%i, %i", c->node_array[0]->data, c->node_array[1]->data);
     return 0;
 }