Convert string to float or double

Question

I am trying to convert a string to a float or double, however none of the standard C/C++ methods seem to work. I have tried:

atof
strtof
strtod
sscanf

In each case, I get an error message when trying to do cleos set contract... along the lines of:

Error 3070000: WASM Exception
Error Details:
env.strtod unresolveable
pending console output:

Is there a way to convert a string to a float or double that I can use?

Answer 1

I recently had this problem. I discovered that atoi() actually works (nothing else did). so I wrote it like this:

float token::stof(std::string s, float def)
{   
    if (s == "") return def;
    std::size_t i = s.find(".");
    int digits = s.length() - i - 1;
    s.erase(i, 1); 
    return atoi(s.c_str()) / pow(10, digits);
}

Answer 2

I hope this can help

double stringtodouble(string str)
{
 double dTmp = 0.0;
 int iLen = str.length();
 int iPos = str.find(".");
 string strIntege = str.substr(0,iPos);
 string strDecimal = str.substr(iPos + 1,iLen - iPos - 1 );
 for (int i = 0; i < iPos;i++)
 {
  if (strIntege[i] >= '0' && strIntege[i] <= '9')
  {
   dTmp = dTmp * 10 + strIntege[i] - '0';
  }
 }
 for (int j = 0; j < strDecimal.length(); j++)
 {
  if (strDecimal[j] >= '0' && strDecimal[j] <= '9')
  {
   dTmp += (strDecimal[j] - '0') * pow(10.0,(0 - j - 1));
  }
 }
 return dTmp;
}