half adder notebooks added

%% Cell type:code id: tags:

``` 

```

%% Cell type:code id: tags:

``` python

from qiskit import *

from qiskit.tools.visualization import plot_bloch_multivector

from qiskit.tools.visualization import plot_histogram

# Creating a circuit with 3 quantum bits and 2 classical bits

qc = QuantumCircuit(3,2)

# Preparing inputs

qc.x(0) # Comment this line to make Qbit0 = |0>

qc.x(1) # Comment this line to make Qbit1 = |0>

# no changes to Qbit2 (stays |0> always)

qc.barrier()

# Applying AND operation and put result to Qbit2

qc.ccx(0,1,2)

qc.barrier()

# Applying XOR operation and put result to Qbit1

qc.cx(0,1)

qc.barrier()

# Reading outputs

qc.measure(1,0) # Reading XOR value ( sum bit )

qc.measure(2,1) # Reading AND value ( carry-out bit )

#qc.draw(output='mpl')

# Run the experimient 1024 times and get stats

counts = execute(qc,Aer.get_backend('qasm_simulator')).result().get_counts()

print(counts)

#credit: https://lahirumadushankablog.wordpress.com/2020/02/04/quantum-half-adder-and-full-adder/

```

%% Output

    {'10': 1024}