Problem with string to numeric conversion

I am inclined to suspect that Borland C++ compiler 5.02 is seemingly full of bugs. Even though my C++ codes could be bug free, it reported External errors on compiling and failed to create an EXE file to run.

Thanks to Mr. Salem, I have successfully compiled the above codes using the new and free C++ compiler CODE::BLOCK8.02 suggested by him in another thread. The program now works as it is supposed to work, except for the part on string to numeric conversion.

I still encounter problem with conversion of string variable to numeric variable using strtof() function call. It seems that that function requires a char instead of string for the conversion. Is it possible then to assign the values of a string variable to a char variable and use that function for conversion?
Is there any other way to do the conversion of a string to numeric variable?

The problematic part has been remarked out to prevent failure in compiling the codes.
// convert string to numeric variable
// weight = strtod(concate,&endptr);

Could somebody please help?

Thanks.

// inkey-Working        by YBM
#include <conio.h>
#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <math.h>
using namespace std;

string spaz(int,string);
string datainp(string,int);
void msg() {cout << "\nPress Esc to Exit, Any other key to continue."; }
void presskey()
{
cout << "\n\nAny other key to continue.";
cin.ignore();
// cin.get();
// system("CLS");
}

void msg2()
{
cout << "\n// INPUT TYPE CONTROL";
cout << "\n// ------------------";
cout << "\n// Weight   Condition 3 Numbers and decimals only ";
cout << "\n\n";
}

char *endptr;
double weight;
std::string sweight;
int xc=0;
int condi;
std::string xcon;
char xconcate;
int getche(void);
int main(void)
{
  const char* xconcate;
  string efield="";
  // Weight Condition 3 Numbers and decimals only
  sweight="";
  efield="Weight";
  condi=3;
  sweight=datainp(efield,condi);
  cout << "\n  Validated Numbers and decimal, Weight: " << sweight << endl;
 return 0;
}
//   Data Entry subroutine
string datainp(string efield,int condi)
{
int xcond=condi;
int c;
int extended = 0;

redo:
std::string concate = "";
msg2();
msg();
condi==xcond;
cout << "\nCondition :" << condi << endl;
cout << "\n\n   Enter "<< efield << ": ";
  do
  {
    c = getche();
    if (c==27) { break; }
    char inp=c;       // assign char from ASCII code Backspace's ASCII code is 8
    if (!c)
      extended = getche();
      if (extended) {     }
      else if (condi==3) {      // Only Numbers and decimal allowed
        if ((c >=48 && c <=57) || (c>=46 && c<=46))
        {
          concate += inp; // string concatenation.. The character isn't extended
        }
        else { concate=spaz(c,concate);}
       }
  } while (c != 13);        // ascii 13 is <enter> or <carriage return>
  int len = concate.length();
  cout << "\n  String length =" << len << " chars" << endl;
  if (condi==3)       // Coversion from string to numeric.
  {
  cout << "\n  Weight entered as string = " << concate;
//  convert string to numeric variable
//   weight = strtod(concate,&endptr);
   cout <<"\n\n  strtod(concate,&endptr) Conversion from string to number is not working.. \n  Test weight is numeric, weight*10 = " << weight*10 << " " << endl;
  }
  return concate;
}  // main terminate

//   SUBROUTINE TO MOVE CURSOR POSITION
string spaz(int xc,string xconcate)
{
  if (xc !=8)    // not backspace
  {
    cout << "\x08";
  }
  else
  {
    int len = xconcate.length();
    if (len >0)
    {
      cout << " ";
      cout << "\x08";
      xconcate=xconcate.substr(0,len-1);
    }
    else
    {
      cout << " ";
    }
  }
return xconcate;
}

yonghc

Junior Poster in Training

55 posts since Aug 2009

Reputation Points: 39

Solved Threads: 0

Problem with string to numeric conversion

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