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//the pure C way
#include <stdlib.h>
#include <stdio.h>

void square_ref(int *x){
	*x = *x*(*x);
}

int square(int x){
	return x*x;
}

int main(int argc, char **argv){
	int test, test2;

	printf("Dear user, please give me an arbitrary number:\n");
	scanf("%d", &test);

	test2 = test;

	square_ref(&test);
	printf("%d\n", test);

	test2 = square(test2);
	printf("%d\n", test2);

	return 0;
}

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//The C++ way
#include <iostream>

using namespace std;

void square_ref(int &x){
	x = x*x;
}

int square(int x){
	return x*x;
}

int main(int argc, char **argv){
	int test, test2;

	cout << "Dear user, please give me an arbitrary number:" << endl;
	cin >> test;

	test2 = test;

	square_ref(test);
	cout << test << endl;

	test2 = square(test2);
	cout << test2 << endl;

	return 0;
}

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#include <stdio.h>
int aufgabe4_1(int x);
int aufgabe4_2(int x);


int aufgabe4_1(int x)
{
    aufgabe4_2(x * x);
    return x;
}

int aufgabe4_2(int x)
{
    aufgabe4_1(x + x);
    return x;
}

int main()
{
    //hier kommt der Funktionsaufruf:
    aufgabe4_1(1);
}