Unformatted Character Input

// flags
enum Ttoken {FLOAT, ENTER, IGNORE};
enum Tfloat {WHOLEPOS, FRACTION, NEGATIVE, NEG_FRACTION};

// global constants
const unsigned BUF_SZ =10; // extra buffer to facilitate '-' & '.'
const int MAX_INTEGER =15;

const char WELCOME[]="Welcome to the Table Program.";
const char ENTER_FLOAT[]="\nEnter table no. Any number less than 9 digits.\n";
const char ENTER_INT[]="\nEnter multiplier no. Any positive whole number less than 15.\n";
const char AGAIN[]="\nPress y to repeat. Any other key to end.";

// global variables
Ttoken currToken;
Tfloat floatType;
unsigned currInput;
char buf[BUF_SZ];
int currInputNo;
float fVar;
int iVar;

//function headers
Ttoken GetFloat();
void GetInt();

Ttoken GetFloat()
{
char ch;
cin.get(ch);


switch(ch) // test input character
{
case '0' :
case '1' :
case '2' :
case '3' :
case '4' :
case '5' :
case '6' :
case '7' :
case '8' :
case '9' :

// handle buf overflow
if(floatType==NEG_FRACTION && buf[BUF_SZ-1])
currToken =IGNORE; // token is ignored

if((floatType==FRACTION || floatType==NEGATIVE) && buf[BUF_SZ-2])
currToken =IGNORE; // token is ignored

if(floatType==WHOLEPOS && buf[BUF_SZ-3])
currToken =IGNORE; // token is ignored


else
{
currToken =FLOAT; // float
break;

}


case '-':
if(buf[0]) // '-' accepted only once
{
currToken= IGNORE;
break;
}
else
{
floatType=NEGATIVE;
currToken= FLOAT;
break;
}

case '.':

if(floatType==FRACTION)
{
currToken= IGNORE;
break;
}
else
{
if(floatType==NEGATIVE)
floatType=NEG_FRACTION;

else
floatType=FRACTION;

currToken= FLOAT;
break;
}


case '\n':
currToken =ENTER;
break;
default :
return currToken =IGNORE;

}//switch(ch)

switch(currToken) // test parser flag
{ // and process input

case FLOAT: // parses number
{
buf[currInput]=ch;
currInput++;
return currToken =FLOAT;
}

case ENTER: // sets float variable
fVar =atof(buf);
return currToken =ENTER;


}//switch


};// GetFloat()

void
GetInt()
{
char ch;
cin.get(ch);

switch(ch) // test input character
{
case '0' :
case '1' :
case '2' :
case '3' :
case '4' :
case '5' :
case '6' :
case '7' :
case '8' :
case '9' :
cin.putback(ch);

do
{
cin>>iVar;
}while(iVar<1 || iVar>MAX_INTEGER);

default:
;

}//switch

}//GetToken()

void main()
{
int loop=0;

clrscr();
cout<<WELCOME;

do // main loop
{
// initialise variables
currInput = 0;
for(int i=0;i<BUF_SZ; i++)
buf[i] =0;
fVar =0;
iVar =0;



if(loop)
{
cin.ignore(); // take '\n' from istream
clrscr();
}
cout<<ENTER_FLOAT;

do // parse input for float
{
GetFloat();
}while(currToken!=ENTER);


do
{
clrscr();
cout<<ENTER_INT;
GetInt();
}while(!iVar);
cin.ignore(); // for '\n'

cout.setf(ios::fixed);
cout<<"\nThe "<<fVar<<" times table to "<<iVar<<" is:-\n";
for(int ii=1; ii<=iVar; ii++)
cout<<ii*fVar<<endl;

cout<<AGAIN<<endl; // loop?
loop=1;
}while(cin.get()=='y');


};