test01.c

#include <stdio.h>

struct container {
    int var1;
    char *var2;
    void (*repr)(struct container *c);
};

void dumper(struct container *c) {
    printf("var1=[%d]\t", c->var1);
    printf("var2=[%s]\n", c->var2);
}

int main()
{
    struct container c =  {.var1 = 19, .var2 = "Cat", .repr = dumper};
    c.repr(&c);
    return 0;
}