Array of Strings

[vinay3744]

Hi

I am stuck at this....basically i am very new to c+ programming and would like to know how to create a multi dimensional array of strings.

Also i would like to create a default multidimensional array of strings of the size mxn = 3000 x 5000. Is it possible in C++. can u give me suggestions on this as well....

Many thanks

Vinay

[r035198x]

Hi

I am stuck at this....basically i am very new to c+ programming and would like to know how to create a multi dimensional array of strings.

Also i would like to create a default multidimensional array of strings of the size mxn = 3000 x 5000. Is it possible in C++. can u give me suggestions on this as well....

Many thanks

Vinay

Have you read any tutorial on strings and/or arrays in C++ yet?

[Savage]

Hi

I am stuck at this....basically i am very new to c+ programming and would like to know how to create a multi dimensional array of strings.

Also i would like to create a default multidimensional array of strings of the size mxn = 3000 x 5000. Is it possible in C++. can u give me suggestions on this as well....

Many thanks

Vinay

Using c arrays that would be:

string array[m][n]....[x];

using c++ STL's vector it would be much more complicated,it's better for now that you use it like this(until you find some good books or tutorials as our admin suggested).

About your second question,typedef it:

typedef name string[3000][5000];

Savage

[vinay3744]

Using c arrays that would be:

string array[m][n]....[x];

using c++ STL's vector it would be much more complicated,it's better for now that you use it like this(until you find some good books or tutorials as our admin suggested).

About your second question,typedef it:

typedef name string[3000][5000];

Savage

Thanks a lot....


Is it possbile to have array upto sizes of 3000 x 5000 in Visual C++?? Cause when i try the same thing with char; it stops at 100 x 5000.

anyways i will try it...

thnx

[Savage]

Thanks a lot....


Is it possbile to have array upto sizes of 3000 x 5000 in Visual C++?? Cause when i try the same thing with char; it stops at 100 x 5000.

anyways i will try it...

thnx

It all depends on your RAM

If you have more of it,you can have bigger arrays(Or if you have lots of free RAM).

Savage

[vinay3744]

It all depends on your RAM

If you have more of it,you can have bigger arrays(Or if you have lots of free RAM).

Savage

Thanks savage

I have 512 Mb Ram right now....outta which i shud be able to spare 200 mb easily at one time....Also I am using dev c++ right now.. do you think that creates a problem?

I have developed a following mini program which shud specify the size of an array....it works for normal int and char types....but doesnt work for a sting type....can u suggest any changes?

#include <iostream>
#include <stdio>
#include <string>
using namespace std; // I dont really know what this means.....

int main()

{
string a[30][50];
std::cout<<sizeof(a);

std::cin.get();

}


thnks

[Savage]

Thanks savage

I have 512 Mb Ram right now....outta which i shud be able to spare 200 mb easily at one time....Also I am using dev c++ right now.. do you think that creates a problem?

I have developed a following mini program which shud specify the size of an array....it works for normal int and char types....but doesnt work for a sting type....can u suggest any changes?

#include <iostream>
#include <stdio>
#include <string>
using namespace std; // I dont really know what this means.....

int main()

{
string a[30][50];
std::cout<<sizeof(a);

std::cin.get();

}


thnks

Ok,lets see:

1.Please use code tags(select your code in Message Editor and click on # button)

2.using namespace std: what this means is that you are using functions from that namespace,when you have it declared you don't need to use std::cout,std::cin,you can just use cout,cin...

For future info you can check C++ articles zone.In that blue menu bellow "thescripts developer network",choose articles and then navigate to c++.
Then choose "Programming classes by Gannon11".

Right now I don't have a compiler at my hand,but can you tell me how it doesn't work.Is there any error,do you get something strange from sizeof?

Savage

[vinay3744]

Ok,lets see:

1.Please use code tags(select your code in Message Editor and click on # button)

2.using namespace std: what this means is that you are using functions from that namespace,when you have it declared you don't need to use std::cout,std::cin,you can just use cout,cin...

For future info you can check C++ articles zone.In that blue menu bellow "thescripts developer network",choose articles and then navigate to c++.
Then choose "Programming classes by Gannon11".

Right now I don't have a compiler at my hand,but can you tell me how it doesn't work.Is there any error,do you get something strange from sizeof?

Savage

ok....i did as u suggested...

I used the following code...

    #include <iostream>
 
    #include <string>
    using namespace std;
 
    int main()
 
    {
        string a[30][50];
        cout<<sizeof(a);
 
        cin.get();
 
    }

Now i am getting the output window showing a result of 600000. When i use dimensions more than 300 x 500, it just gives me windows not responding error......does it have to do with the ram of my system...or is it somethin else?

Also how many characters by default can u use in every attribute in the array...?

thnx again.....u have helped me a lot...

[Savage]

ok....i did as u suggested...

I used the following code...

    #include <iostream>
 
    #include <string>
    using namespace std;
 
    int main()
 
    {
        string a[30][50];
        cout<<sizeof(a);
 
        cin.get();
 
    }

Now i am getting the output window showing a result of 600000. When i use dimensions more than 300 x 500, it just gives me windows not responding error......does it have to do with the ram of my system...or is it somethin else?

Also how many characters by default can u use in every attribute in the array...?

thnx again.....u have helped me a lot...

Well,300x500 is about 57.22Mb of RAM.

I suppose that stack arrays have limited amount of memory(If I'm not wrong it was 4096 bytes in C)

Try allocating it dynamicly:

string **a; //pointer to pointer to a string
int x=300;
int y=500;
 
a=new string*[x] //Allocates first dimension
for(int i=0;i<x;i++)
{
  a[i]=new string[y];//Allocates sub array
}
 

and then you can use as a normal array.

After you have completed everything you need with string a[x][y],because it was dynamicly allocated you must deallocate it:(Reverse of allocation process)

for(int i=0;i<x;i++)
{
  delete[] a[i];//deletes sub array 
}
 
delete[] a;//Delete first dimension
 

You must allocate it and dealocate it like this because heap memory is not contiguous as stack memory.

Tip:by adding to [code] tag ="language",you can achieve syntax highlighting.

e.g:[code="cpp"]

Savage

[vinay3744]

Well,300x500 is about 57.22Mb of RAM.

I suppose that stack arrays have limited amount of memory(If I'm not wrong it was 4096 bytes in C)

Try allocating it dynamicly:

string **a; //pointer to pointer to a string
int x=300;
int y=500;
 
a=new string*[x] //Allocates first dimension
for(int i=0;i<x;i++)
{
  a[i]=new string[y];//Allocates sub array
}
 

and then you can use as a normal array.

After you have completed everything you need with string a[x][y],because it was dynamicly allocated you must deallocate it:(Reverse of allocation process)

for(int i=0;i<x;i++)
{
  delete[] a[i];//deletes sub array 
}
 
delete[] a;//Delete first dimension
 

You must allocate it and dealocate it like this because heap memory is not contiguous as stack memory.

Tip:by adding to [code] tag ="language",you can achieve syntax highlighting.

e.g:[code="cpp"]

Savage

hey

thanks....this works for now....

but will this work when i need the whole 300 X 500 attributes at once.....cause i need to input that many values for my program....(someting like getting input as all the search results from google!!!!)

[Savage]

hey

thanks....this works for now....

but will this work when i need the whole 300 X 500 attributes at once.....cause i need to input that many values for my program....(someting like getting input as all the search results from google!!!!)

I'm not sure that I understood this.

Can you rephrase it or show me some simple code example?

Savage

[vinay3744]

I'm not sure that I understood this.

Can you rephrase it or show me some simple code example?

Savage

ok...i do not have a concrete example right now as i have just started programming for the program....but i will try explaining it again!..

basically if i want to input a whole set of values intead of inputting values one by one, will the dynamic allocation for the string array work? or do I need to get more memory and declare the whole string array at once....??

[Savage]

ok...i do not have a concrete example right now as i have just started programming for the program....but i will try explaining it again!..

basically if i want to input a whole set of values intead of inputting values one by one, will the dynamic allocation for the string array work? or do I need to get more memory and declare the whole string array at once....??

Of course it will.Also you can change size of dynamic array at the run time.Say that you are reading in file that contains 10 rows and 3 columns of strings.Why allocate 300x500 when you can just allocate 10x3,this will ensure that you have more free memory and that you don't use more memory than you need to.

Savage

[vinay3744]

Of course it will.Also you can change size of dynamic array at the run time.Say that you are reading in file that contains 10 rows and 3 columns of strings.Why allocate 300x500 when you can just allocate 10x3,this will ensure that you have more free memory and that you don't use more memory than you need to.

Savage

ohk....thats sooo coooL!!!..

thanks man....i have just started programming and this helps a lot....

I will keep in touch...

cheers

[Savage]

ohk....thats sooo coooL!!!..

thanks man....i have just started programming and this helps a lot....

I will keep in touch...

cheers

I'm more than happy to help you.

And,of course,feel free to post again if you find yourself stuck.

Savage

[vinay3744]

hello

is it possible to use the same syntax to declare a float array? just by changing the data type from string to float?

[vinay3744]

Also if i want to input some values in the array using for functions or maybe call the array from another function in the form a[x][y]; is it possible? really apperciate ur help!

thnx