title: IOS:Convert string to hexadecimal array
body: <p>i have string representing data .i need to convert those data to the hex array .By using the hex array data i can pass it to the CRC for writing to the peripheral </p>
  
  <p>My string data is like this </p>
  
  <pre><code>          NSString *stringsdata=@"helloworld1234567812345q";
  </code></pre>
  
  <p>i need to convert to hex format array like </p>
  
  <pre><code>       {0x0h,0x0e............0x0q}. 
  </code></pre>
  
  <p>so by using this array  i can keep the data in the crc and write it to the peripheral data as        </p>
  
  <pre><code>            Byte comm[24];
              comm[0]=0x01;
              comm[1]=0x30;
              comm[2]=0x62;
              comm[3]=0x00;................
  </code></pre>
  
  <p>have tried with many possible solutions but not luck.can any body help will be greatly appreciated.</p>