如何实时组合十六进制值？

Question

To give a context, I have an incoming stream of Hex values that is getting written to a CSV file which are in the format shown below.

20 5a 20 5e 20 7b 20 b1 20 64 20 f8 ...

I can not change the way the data is flowing in, but before it gets written to a CSV file I want it in this format below.

205a 205e 207b 20b1 2064 20f8 ...

As the data is coming, I need to process it and store it in the format shown above. One of the ways I tried was just bitshifting and doing logical OR which would store the result in a variable. But all I have here is a pointer pointing to a buffer where the data will be flowing into. I have something like this.

uint8_t *curr_ptr;
uint8_t* dec_buffer=(uint8_t*)calloc(4000,sizeof(uint8_t)*max_len);
init=dec_buffer;
curr_ptr=init+((count)*max_len);

for(int j=17;j<=145;j+=1){

        fprintf(f_write[file_count],"%02x ", *(curr_ptr+j));

if(j>0 && j%145==0){

       fprintf(f_write[file_count],"\n");

Answer 1

Effectively you want to remove every other space. Why not something like this?

for(int j=17;j<=145;j+=1){
    fprintf(f_write[file_count], j%2 ? "%02x " : "%02x", *(curr_ptr+j));

Not sure if you should be printing spaces after the odd values of j or the even ones, but you can sort that out.