8 replies to this topic

[jasonalien]

Hello everyone,
I have a string array with a length of 360 strings. But only a small amount of the strings are full, like 10-20 strings. And the data inside the strings is like that :

-91dBm
-93dBm
-88dBm
-89dBm
-88dBm
-89dBm
-92dBm
-91dBm
-92dBm
-90dBm
-90dBm
I need to make some calculations on this data. So How could I get rid of the dBms after numbers? And how could I conver them to negative integers.
Thanks in advance.

[kernelcoder]

You mean all those above data contains in a single array of char? Or, only one of them will be in a string at a time (as example -91dBm)?

If an array of chars contains data like "-91dBm", you can use atoi function go get the data. As example,

int frequency = atoi("-91dBm"); /* here frequency variable will have -91 in it*/

[jasonalien]

only one data is on one string, for example -91dBm is in one string.

[Brandon W]

only one data is on one string, for example -91dBm is in one string.

What kernel mentioned will still work in this case, did you manage to get it working though, bahadirtr?

[jasonalien]

                       string yirmidorty[360]

                        int baha[360];
                        for(int i = 0; i<360;i++)
                        {
                        baha[i]=atoi(yirmidorty[i]);
                        cout<<baha[i]<<endl; 
                        
                        }

My compiler says that I'm giving invalid arguments to atoi.. As I see atoi accepts char array but not strings. Is there a way to make atoi do that?
Thanks..

[jasonalien]

I found istringstream function. It seems useful but I couldn't make this code work :

					    int baha[360];
					    for(int i = 0; i<360;i++)
					    {
					    istringstream(yirmidorty[i])>>baha[i];
						 cout<<baha[i]<<endl;
					    }

[Brandon W]

I have never heard of the istringstream function before, if you wish to use it I'll look it up but to convert your string to a C string, simply use the function .c_str() on the string.

e.g.

char * cString= (char*)yirmidorty[i].c_str();

[notes]

It's nice to write own function which is really simple.I wote my function which was changing string like 22-3+(31*3) to two stacks one integer type with values second char type with operators. In your case it would be much simplier cause you have to read from '-' till next digit is not integer.
function that checks would look really simple like :

if (((int)num[0] > 47) && ((int)num[0] <58) )
return true;
return false;

You are comparing ASCII digits. Then you can append character to a temporary string where you'll have only numbers.
This is working prototype, I leave to you recognizing whenever its negative or positive int.

bool is_number(char c);
int str_to_int(string str);
int _tmain(int argc, _TCHAR* argv[])
{
string str ="-96dBm";
int result = str_to_int(str);
cout << "String: " << str<< "\nInt: " << result<< endl;
system("PAUSE");
return 0;
}
bool is_number(char c) {
if ( ((int)c > 47) && ((int)c <58) )
return true;
return false;
}
int str_to_int(string str) {
int myResult = 0; // IMPORTANT to initialize this int.
string temp;
int j = 1;
// Want to start from 1 cause first char is '-'
	 // You may want to change is_number function to omit this.
while (is_number(str[j]) ) {
temp += str[j];
j++;
}
// Now we have number in temp;
int tempSize=temp.length()-1;
for (int i = 0; i <tempSize; i++ ) {
myResult*=10; // if 0 still 0
myResult+=atoi(&temp[i]);
}
return myResult;
}

Edit : This is ms vc++ so to get this working youll need to include in stdafx.h:

#pragma once
#include "targetver.h"
#include <stdio.h>
#include <tchar.h>
#include <iostream>
#include <string>
using namespace std;

Or just make propper includes in your IDE ;-)

Hope this was helpful,
notes.

[jasonalien]

thank you