How to Convert e.x. 2/3 or 1/2 in input to float in cpp

string s="2/3";
float x=stod(s);

CodePudding user response：

You could try something like:

int a,b;
string s="2/3";
sscanf(s.c_str(), "%d/%d", &a, &b);
float x = float(a)/b;

Of course, you have to do some validations around b being zero.

CodePudding user response：

You can use std::string::find() to find the / char, and then use std::string::substr() to split the string into its numerator and denominator portions.

Then use std::stod() to convert each to a number:

std::string numerator = s; 
std::string denominator = "1";

auto pos = s.find("/");
if (pos != std::string::npos)
{
    numerator = s.substr(0, pos);
    denominator = s.substr(pos 1);
}

double n, d;
double result = 0;
try
{
    n = std::stod(numerator);
    d = std::stod(denominator);
    if (d != 0)
    {
        result = n / d;
    }
}
catch(std::exception& ex)
{
    // parse error
}