This page shows some simple examples for pass a variable to a function by reference. It is implemented as part of a c++ series of exercises , that I did.

1. The code was taken from an ECC project.
   Example one is a function that counts the number of 1 bits in an unsigned char.


1. void c_e_ccc_correct::bit_count(const unsigned char& d) {
2.   unsigned char i, j;
3.   bit_cnt=0;
4.   for(i = 0, j=1; i <= 7; i++) {
5.     if( d & j ) bit_cnt++;
6.     j *= 2;
7.   }
8. }


2. This example was taken also from the ECC code. This time two classes are passed by reference.
   
   
   1. c_e_ccc_correct::c_e_ccc_correct(const c_ecc& prev, const c_ecc& curr) {
   2.   total_bit_cnt=0;
   3.   for(i=0; i <= 2; i++) {
   4.     ecc_c[i]=prev.ecc[i] ^ curr.ecc[i];
   5. #ifdef DGB_1 //{
   6.     cout << "xor " << hex << (unsigned)ecc_c[i] << " " << (unsigned)prev.ecc[i] << " " << (unsigned)curr.ecc[i] << endl;
   7. #endif //}
   8.     bit_count(ecc_c[i]);
   9.     total_bit_cnt += bit_cnt;
   10.   }//for

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