C++ Coding Explaining & reviewing

#include <iostream>

#include <fstream>

#include <string>

using namespace std;

void sm(int scl, int sda);

enum states {

s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14, s15, s16

};

struct i2c {

int scl;

int sda;

int item;

};

struct i2c traces[1000];

int trace_length;

int main()

{

int item, scl, sda, index;

string trace0;

ifstream myfile; /* Naming the file to open*/

string myline;

char read_write_mode = 'R';

bool ack = false;

int read_count = 0;

int write_count = 0;

int ack_count = 0;

int nack_count = 0;

trace0 = "t0.txt"; /* Choosing the file trace*/

myfile.open(trace0.c_str()); /* Open file c_str is for the first line*/

getline(myfile, myline); /* First line*/

index = 0;

while (!myfile.eof()) /* Assigning the clock and data from file to code*/

{

myfile >> item >> scl >> sda;

traces[index].item = item;

traces[index].scl = scl;

traces[index].sda = sda;

index++;

}

trace_length = index; /* to count traces*/

myfile.close();

for (index = 0; index < trace_length; index++)

{

sm(traces[index].scl, traces[index].sda);

}

if ((scl == 0 && sda == 0) && (scl == 1 && sda == 0) && (scl == 0 && sda == 0))

{

ack_count++;

}

else

nack_count++;

cout << "ack = " << ack_count << endl;

cout << "nack = " << nack_count << endl;

system("pause");

}

void sm(int scl, int sda)

{

static int ps = 0;

static int ns = 0;

static int address;

static int r_w;

static int temp;

static int k;

static int index;

static bool ack;

static bool nack;

ps = ns;

cout << "ps " << ps << endl;

cout << "scl " << scl << " " << "sda " << sda << endl;

cout << "Address = " << temp << endl;

switch (ps)

{

case s0: if ((scl == 1) && (sda == 0)) /* IDLE*/

ns = s1;

else

ns = s0;

break;

case s1: if (scl == 1) /* START*/

ns = s1;

else

ns = s2;

k = 0;

temp = 0;

break;

case s2: if (scl == 0)

ns = s2;

else

ns = s3;

break;

case s3: if (scl == 1)

ns = s3;

else

ns = s4;

temp = temp << 1;

temp = temp + sda;

k = k + 1;

break;

case s4: if (k != 8)

ns = s2;

else {

ns = s5;

address = temp >> 1;

r_w = temp & 1;

cout << "address = " << hex << address << endl;

}

break;

case s5: if (scl == 0)

ns = s5;

else

ns = s6;

break;

case s6: if (scl == 1) /*ACK = 0, NACK = 1 */

ns = s6;

else

ns = s7;

break;

case s7: if (ack == false)

ns = s0;

else

ns = s8;

break;

case s8: if (scl == 0)

ns = s8;

else

ns = s9;

break;

case s9: if (scl == 1)

ns = s9;

else

ns = s10;

break;

case s10: if (k != 8)

ns = s8;

 else

 ns = s11;

break;

case s11: if (scl == 0)

ns = s11;

 else

 ns = s12;

break;

case s12: if (scl == 1)

ns = s12;

 else

 ns = s13;

break;

case s13: if (ack == false)

ns = s0;

 else

 ns = s14;

break;

case s14: if (scl == 0 && sda == 0)

ns = s15;

 else

 ns = s14;

break;

case s15: if (scl == 0 && sda == 0)

ns = s15;

 else

 ns = s16;

break;

case s16: if (scl == 1 && sda == 0)

ns = s16;

 else

 ns = s0;

break;

}

}