Code

 Header...
// Read in one non-blank line, stripping final spaces
// Allocate the resulting character array
#define BUFLEN 28
 char * readaline(void){
   ... 

»  char input[BUFLEN], *output=NULL;
»  int len;

»  while (1) {
»    if (fgets(input, BUFLEN, stdin)==NULL) {
»      fprintf(stderr, "Out of input!!\n");
»      exit(99);
}

    // Find the final non-space (if any)
»    for (len=strlen(input); len>0&&isspace(input(len-1)); --len) {
}/// Empty loop: the for() does all the work
»    inputlen='\0';// Truncate the input

»    if (input0=='\0') // Blank line
      continue;

»    output=malloc(1+len);
»    if (output==NULL) {
»      fprintf(stderr, "Out of memory!\n");
»      exit(98);
}
»    strncpy(output, input, len+1);
»    return output;
  }

}

 int main(){
   ... 

»  double mass;
»  char *desc;

»  printf("Please enter the mass\n");
»  scanf("%lg", &mass);

»  printf("Now please enter a short description\n");
»  desc=readaline();

»  printf("Mass: %g description: %s\n", mass, desc);
  
»  return 0;
}