2 DIMENSIONAL ARRAY!!!

[G6RoizwU]

As of now my program as the user input an expression like *2x and then the program outputs it as

*
2
x

I am wanting to display zeros next to the elements, 2 columns of zeros so the output will be

* 0 0
2 0 0
x 0 0

This is my code

int main()
{

string s;
cout << "Input the prefix expression.\n" ;
cin >> s;
cout << "The expression tree is:\n" ;

int row = s.length();
int col = 2;
int array[row][col];
int i, j, c;

for (j = 0; j < row; j++)
for (c = 0; c < col; c++)
for (i = 0; i < s.length(); i++)
{
cout << s[i] << array[row][col] << endl ;
}

it outputs

*2293584
22293584
x2293584
*2293584
22293584
x2293584
*2293584
22293584
x2293584
*2293584
22293584
x2293584
Edit/Delete Message

[jfolk]

std::string s;
std::cout << "Input the prefix expression.\n";
std::cin >> s;
std::cout << "The expression tree is:\n";
for(size_t i = 0; i < s.length(); i++)
    std::cout << s[i] << "00" << std::endl;

[TaikoDragon]

int array[row][col];
Well first of all why are you using integers? Are you dealing with numbers or characters???
Also you are using with the array without initializing it, so it's garbage data.

for (j = 0; j < row; j++)
for (c = 0; c < col; c++)
for (i = 0; i < s.length(); i++)
{
cout << s[i] << array[row][col] << endl ;
}

in those lines you are not using the looping variables j and c when you access the array...
cout << s[i] << array[row][col] << endl ;
so you are only accessing static positions that actually are outside the bounds of the array. You should look-up the documentation on usage of arrays.

[JCED]

If you want it in an array:

#include <iostream>
#include <string>

using namespace std;

int main()
{
	string input;

	cout << "Input the prefix expression." << endl;
	cin >> input;
	cout << "The expression tree is:" << endl;

	string expr_tree[input.length()];
	
	// This "*(new string(1, input[i]))" may be confusing.
	// Basically, it makes the new string declared on the heap
	// (see Wikipedia if you don't know what that is). Then it dereferences
	// it because we're not dealing in pointers to strings
	for (int i = 0; i < input.length(); i++) {
		expr_tree[i] = *(new string(1, input[i]));
		expr_tree[i] += " 0 0";
	}

	for (int i = 0; i < input.length(); i++) {
		cout << expr_tree[i] << endl;
	}

	// we need to clean up because of that "new" back there
	for (int i = 0; i < input.length(); i++) {
		delete expr_tree[i];
	}

	return 0;
}

Vectors will make this a little easier:

#include <iostream>
#include <vector>
#include <string>

using namespace std;

int main()
{
	string input;

	cout << "Input the prefix expression." << endl;
	cin >> input;
	cout << "The expression tree is:" << endl;

	vector<string> expr_tree;

	for (int i = 0; i < input.length(); i++) {
		expr_tree.push_back(*(new string(1, input[i])));
		expr_tree[i] += " 0 0";
	}

	for (int i = 0; i < expr_tree.size(); i++) {
		cout << expr_tree[i] << endl;
	}

	return 0;
}

[buffbill]

What`s wrong with the first response from jfolk?

[TaikoDragon]

nothing but I was assuming that the "00" was meant to be real data not a static string .. else why bother with an array or anything else

[G6RoizwU]

thanks for all the advice. I was able to get it to output the zeros however that was just so I could try and figure out the next problem. They are meaningful, if one of the operands (+, -, *, /) are entered then the second column needs to be the index of it's left child and the 3rd column its right so that the output will be
* 1 2
2 0 0
x 0 0

The only way I know to try and accomplish this is by a switch statement but I do not know how to try and find the index.

#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
   char s[50];
   cout << "Input the prefix expression.\n" ;
   cin >> s;
   cout << "\nThe expression tree is:" ;

   
   int row = strlen(s);
   int col = 2;
   char a[10][10];
   int i, j, c;
   int pos;

   for (j = 0; j < row; j++)
   {
       a[j][0] = s[j];

   for(i = 1; i <= col; i++)
   {
       a[j][i] = '0';
       
       switch (s[j]) {
         case '+':
         case '-':
         case '*':
         case '/':
         
           a[j][i] = ;
           break;
           }
   }
   }

   for (j = 0; j < row; j++)
   {
       cout << "\n";
   for(i = 0; i <= col; i++)
   {
       cout << a[j][i] << setw(2) ;
   }
   }