Question

c++

how can i convert a string to double/float? write a method that takes in a string and converts to double.

example of a string: 4.2 9 7.5 + 2

Notice that each number/operator is separated by a space.

Answer 1

If any corrections needed kindly let me know by comments. I will correct it

Program

#include <iostream>
#include <sstream>
using namespace std;

void convert(string str)
{
    stringstream ss;

    /* Storing the whole string into string stream */
    ss << str;

    /* Running loop till the end of the stream */
    string temp;
    double found;
    while (!ss.eof()) {

        /* extracting word by word from stream */
        ss >> temp;

        /* Checking the given word is double or not */
        if (stringstream(temp) >> found)
            cout << found << " ";

        /* To save from space at the end of string */
        temp = "";
    }
}

// Driver code
int main()
{
    string str = " 4.2 9 7.5 + 2";
    convert(str);
    return 0;
}

Output

4.2 9 7.5 2