C++

Forum

 
reverse an array(convert from void to int error)

valiciousx (26)
I need to write a program which reverse an array using a stack.I have one error which says that can not convert from void to int and I don't know how to approach the error.
the functions. (pop and inverseOrder)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
 
void pop(Stack& S)
{
	Stack aux = S;
	S = S->link;
	delete(aux);
}

void inverseOrder(int v[], int n)
{
	Stack S;
	initStack(S);
	for (int i = 0; i < 0; ++i)
	{
		push(S, v[i]);
	}
	for (int i = 0; i < n; ++i)
	{
		v[i] =pop(S); // here is the error.How to approach this?
	}
	cout << "Reversed array is: ";
	display(v, n);
}
Ganado (6783)
v[i] =pop(S);The return type of your function, pop, is void. That means it doesn't return anything. Yet you are trying to assign the would-be return value of pop(S) to v[i].

Here is an example of a function that returns something:
1
2
3
4
5
6
7
8
 
int something()
{
    return 43;
}

// ...

int thing = something();



What is the definition of "Stack" in your code. If it isn't a pointer, then calling delete aux; doesn't make sense.
Last edited on
valiciousx (26)
Here's the code:
main file
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
 
#include <iostream>
#include "header.h"
using namespace std;

int main()
{

	int n;
	int v[30];
	cout << "Enter the nr of elements: ";
	cin >> n;
	readArray(v, n);
	inverseOrder(v, n);
	return 0;
}

functions file
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
 
#include <iostream>
#include "header.h"
using namespace std;

void initStack(Stack& S)
{
	S = nullptr;
}

void push(Stack& S, int a)
{
	Element*nou = new Element;
	nou->data = a;
	nou->link = S;
	S = nou;
}

void pop(Stack& S)
{
	Stack aux = S;
	S = S->link;
	delete(aux);
}

bool isEmpty(Stack &S)
{
	if (S == 0)
		return true;
	else
		return false;
}

void readArray(int v[], int n)
{
	for (int i = 0; i < n; ++i)
	{
		cout << "v[" << i << "]=";
		cin >> v[i];
	}
}

void display(int v[], int n)
{
	for (int i = 0; i < n; ++i)
	{
		cout << v[i] << " ";
	}
}

void inverseOrder(int v[], int n)
{
	Stack S;
	initStack(S);
	for (int i = 0; i < n; ++i)
	{
		push(S, v[i]);
	}
	for (int i = 0; i < n; ++i)
	{
		v[i] =pop(S);
	}
	cout << "Reversed array is: ";
	display(v, n);
}

header file
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
 
#ifndef HEADER_H_
#define HEADER_H_

struct Element {
	int data;
	Element* link;
};
typedef Element* Stack;
void initStack(Stack& S);
void push(Stack& S, int a);
void pop(Stack& S);
bool isEmpty(Stack &S);
void readArray(int v[], int n);
void display(int v[], int n);
void inverseOrder(int v[], int n);

#endif

Last edited on
Ganado (6783)
Okay so your "Stack" is actually an individual Element pointer that you typedef'd.
So perhaps you want to return something from your pop() function, as I mentioned before.

1
2
3
4
5
6
7
8
9
10
 
int pop(Stack& S)
{
	int value = S->data;
	// your existing code:
	Stack aux = S;
	S = S->link;
	delete aux;
	// return:
	return value;
}

Not tested. There might be other issues.
valiciousx (26)
Yes, it's working now.Thank you for your help!
Topic archived. No new replies allowed.