problem in array assigment

[peripheral]

#include <iostream>
using namespace std;
main(){
       char datan[8]={'0','0','6','0','7','b','4','5'};
       unsigned char data[4]={0};
                data[0]=(datan[0]<<4)+datan[1];
                data[1]=(datan[2]<<4)+datan[3];
                data[2]=(datan[4]<<4)+datan[5];
                data[3]=(datan[6]<<4)+datan[7];
                
  	            cout<<datan<<","<<data<<endl;
  	                
  	            system("pause");        
}

the output is

D:\Dev-Cpp>testdata
00607b45?",0愐u00607b45?"

should it be the same?


what is the resean?

[hamsterman]

It's not the same. simply you dont have \0 at the end of your arrays so they are printed until cout finds one. original array is '00607b45 then' , '?"' is rubbish, then , then '0愐u' is what you created, and '00607b45?"' is there because in your memory datan goes after data.

[peripheral]

thank you very much.


but I use printf("%2x%2x%2x%2x\n",data[0],data[1],data[2],data[3]) ;

the output is

3090d275

shouldn't it be 00607b45?

how can I get the right values?

I don't understand why a 4-length character array contains "0愐u00607b45?",it is too long ,isn't it?

[hamsterman]

Your printing two hex digits here.
'0' is not the same as 0
'0' in fact == 48. dec 48 == hex 30, so you get 30.

[peripheral]

so complicate
I only want to convert a string of hex meaning of 00607b45 to {0x00,0x60,0x7b,0x45}

would you give me a easy way?

[hamsterman]

how about

#include <iostream>
using namespace std;
main(){
       char datan[4]={0x00,0x60,0x7b,0x45};
       unsigned char data[4]={0};
                data[0]=(datan[0]<<4)+datan[1];
                data[1]=(datan[2]<<4)+datan[3];
                data[2]=(datan[4]<<4)+datan[5];
                data[3]=(datan[6]<<4)+datan[7];
                
                  cout<<datan<<","<<data<<endl;//this wont work here
                  cout << hex;
                  for(int i = 0; i < 4; i++) cout << (int)datan[i]
                  cout.put(',');
                  for(int i = 0; i < 4; i++) cout << (int)data[i]
                      
                  system("pause");  //http://www.cplusplus.com/forum/articles/11153/
       cin.get();      
}