// quantum ripple-carry adder from Cuccaro et al, quant-ph/0410184
  OPENQASM 2.0;
  include "qelib1.inc";
  gate majority a,b,c 
  { 
    cx c,b; 
    cx c,a; 
    ccx a,b,c; 
  }
  gate unmaj a,b,c 
  { 
    ccx a,b,c; 
    cx c,a; 
    cx a,b; 
  }
  qreg cin[1];
  qreg a[4];
  qreg b[4];
  qreg cout[1];
  creg ans[5];
  // set input states
  x a[0]; // a = 0001
  x b;    // b = 1111
  // add a to b, storing result in b
  majority cin[0],b[0],a[0];
  majority a[0],b[1],a[1];
  majority a[1],b[2],a[2];
  majority a[2],b[3],a[3];
  cx a[3],cout[0];
  unmaj a[2],b[3],a[3];
  unmaj a[1],b[2],a[2];
  unmaj a[0],b[1],a[1];
  unmaj cin[0],b[0],a[0];
  measure b[0] -> ans[0];
  measure b[1] -> ans[1];
  measure b[2] -> ans[2];
  measure b[3] -> ans[3];
  measure cout[0] -> ans[4];