Project2

// Proj2.cpp
// by Jason Plumb
// Concepts of Programming Languages
// Instructor: Dr. Cooke
//
// Description: This program will input an arbitrary string of characters
// and will convert the number into a floating point representation of the
// character string. It should be noted that this program does not use
// any string conversion routines (such as strtol). This program uses the
// type "double" to store all floating point values, so the value entered
// by the user should be in the range of "double". It should also be noted
// that the two last lines of program output display the number in its floating
// point representation and the number + 3.1415. The display of the final number
// (intput number + 3.1415) may not properly reflect the result due to floating
// point arithmetic inaccuracies. This is not due to any flaw in the input
// string parsing program. This program does not properly handle negative
// numbers, and there is no error checking to ensure that the number entered
// is a valid base 10 number.

// This file was compiled under Visual C++ 5.0

#include <stdio.h>
#include <string.h>
#include <math.h>

void main(){

char buffer[200];
char *pInt; //Pointer to int portion
char *pFrac; //Pointer to the fractional portion
long iInt, iFrac;
int i, iLen;
double fFrac, fAns;
long exp;

memset(buffer, NULL, 200);
iFrac = iInt = 0;

printf("Please enter a string to be converted to floating point: ");

gets(buffer);
if(strlen(buffer)==0){
printf("Nothing given...aborting!");
return;
}//if

printf("The string entered was '%s'\n", buffer);
pFrac = strchr(buffer, '.');

if(pFrac==NULL){
printf("No fractional portion was given...\n");
printf("The fractional portion is 0\n");
fFrac = 0;
}//if
else{

pFrac++;   //Increment pointer over the '.' character
iLen = strlen(pFrac);
for(i=0;i<iLen;i++){
   exp = (long)pow(10,iLen-i-1);
   iFrac += (exp*(pFrac[i]-48));
}//for
printf("The fractional portion is: %d * 10^-%d\n", iFrac, strlen(pFrac));
}//else (fractional portion given)

pInt = strtok(buffer, ".\r\n"); //Get portion before the '.'
if(pInt==pFrac){      //If the int portion same as fraction
printf("No integer portion given...\n");
}//if
else{
iLen = strlen(pInt);
for(i=0;i<iLen;i++){
   exp = (long)pow(10,iLen-i-1);
   iInt += (exp*(pInt[i]-48));
}//for
}//else (int portion given)
printf("The integer portion is: %d\n", iInt);

if(fFrac!=0)
fFrac = (double)(((double)iFrac)/(pow(10,strlen(pFrac))));

fAns = iInt + fFrac; //The result is the integer portion plus the fractional portion
printf("The floating point number is %.15f\n", fAns);
fAns += (double)3.1415;
printf("The floating point number + 3.1415 is %.15f\n", fAns);

}//main