#include<stdio.h>
#include<stdlib.h>
#include<string.h>

typedef struct {
    int mnr;
    char* vnme;
    char* nnme;
} student;

void printstudent(student *std){
    if((std)!=NULL){
        printf("Matrikelnummer:%i, Vorname:%s, Nachname:%s\n",(*std).mnr,(*std).vnme,(*std).nnme);
    }
}

void printstudents(student *std[]){
    int i;
    for(i=0;i<20;i++){
        printstudent(std[i]);
    }
}

void add_student(student *std[]){
    int mnr,i=0;
    char* vnme;
    char* nnme;
    student *s;
    s=malloc(sizeof(student));
    printf("Bitte Matrikelnummer, Vorname und Nachname eingeben:\n");
    scanf("%i",&mnr);
    scanf("%s",vnme);
    scanf("%s",nnme);
    (*s).mnr=mnr;
    (*s).vnme=vnme;
    (*s).nnme=nnme;
    for(i=0;i<20;i++){
        if(std[i]!=NULL){
            std[i]=s;

            break;
        }
    }
}



int main(){
    int i;
    student *karl;
    karl=malloc(sizeof(student));
    (*karl).mnr=785;
    (*karl).vnme="Karl";
    (*karl).nnme="Klausenhausberg";
    printstudent(karl);
    student* studenten[20];
    for(i=0;i<20;i++){
        studenten[i]=NULL;
    }
    studenten[0] = karl;
    printstudents(studenten);
    add_student(studenten);
}