C++ – YlmzCmlttn

atof stof stod problems with local floating point separator in C/C++

Posted on May 7, 2021 by Yılmaz Cemalettin

Today I encounter a problem with my C++ code. I try to convert string to double. Then I realize in my computer std::atof doesn’t work properly. Also others(stof stod) doesn’t not work correctly. Then I decide to find the issue. I write to simple script to print all output of those functions.

//
#include <iostream>
#include <stdlib.h>
int main(int argc, char *argv[])
{
    std::string num = "3.5";
    std::cout<<num<<std::endl;

    double ret = std::atof(num.c_str());
    std::cout<<ret<<std::endl;
    std::cout<<ret+0.1<<std::endl;

    ret = std::stof(num);
    std::cout<<ret<<std::endl;
    std::cout<<ret+0.1<<std::endl;

    ret = std::stod(num);
    std::cout<<ret<<std::endl;
    std::cout<<ret+0.1<<std::endl;
    
    return 0;

}

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//

#include <iostream>

#include <stdlib.h>

int main(int argc, char *argv[])

{

std::string num = "3.5";

std::cout<<num<<std::endl;

double ret = std::atof(num.c_str());

std::cout<<ret<<std::endl;

std::cout<<ret+0.1<<std::endl;

ret = std::stof(num);

std::cout<<ret<<std::endl;

std::cout<<ret+0.1<<std::endl;

ret = std::stod(num);

std::cout<<ret<<std::endl;

std::cout<<ret+0.1<<std::endl;

return 0;

}

Outputs:

//
3.5
3
3.1
3
3.1
3
3.1

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8

//

3.5

3

3.1

3

3.1

3

3.1

…

Introduction OpenCV | Learning OpenCV3 C++

Posted on March 17, 2019March 17, 2019 by Yılmaz Cemalettin

This post series is the Solutions of the Learning OpenCV 3 written by Adrian Kaehler & Gary Bradski Chapter 2: Introduction OpenCV For this chapter, I prepare Cmake file to build the example code

Install OpenCV | Learning OpenCV3 C++

Posted on March 17, 2019 by Yılmaz Cemalettin

This post series is the Solutions of the Learning OpenCV 3 written by Adrian Kaehler & Gary Bradski Chapter 1: Overview In this chapter shows how to install OpenCV in your computer. I use Ubuntu OS, so that I write a shell script for the installing OpenCV you can use it easily.

#!/bin/bash
sudo apt-get update -y
sudo apt-get upgrade -y
sudo apt-get install build-essential -y
sudo apt-get install cmake -y
sudo apt-get install libopenblas-dev -y
sudo apt-get install git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev -y
sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libdc1394-22-dev -y
sudo apt-get install libboost-all-dev -y
sudo apt-get install libncurses5-dev libncursesw5-dev -y
wget https://github.com/opencv/opencv/archive/3.4.0.zip
unzip 3.4.0.zip
cd opencv-3.4.0
mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..
make -j8
sudo make install
sudo apt-get install libboost-all-dev

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#!/bin/bash

sudo apt-get update -y

sudo apt-get upgrade -y

sudo apt-get install build-essential -y

sudo apt-get install cmake -y

sudo apt-get install libopenblas-dev -y

sudo apt-get install git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev -y

sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libdc1394-22-dev -y

sudo apt-get install libboost-all-dev -y

sudo apt-get install libncurses5-dev libncursesw5-dev -y

wget https://github.com/opencv/opencv/archive/3.4.0.zip

unzip 3.4.0.zip

cd opencv-3.4.0

mkdir build

cd build

cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..

make -j8

sudo make install

sudo apt-get install libboost-all-dev

Libraries

Writing a Program | C++

Posted on March 17, 2019March 17, 2019 by Yılmaz Cemalettin

This post series is the Solutions of the Programming — Principles and Practice Using C++ (Second Edition) written by Bjarne Stroustrup Chapter 6: Writing a Program Drill

Nature of Lights | Optics C++

Posted on February 10, 2019March 17, 2019 by Yılmaz Cemalettin

These post series aim to solve examples and problems from Introduction to Optics book which is writen by Frank L. Pedrotti, Leno M. Pedrotti and Leno S. Pedrotti. Chapter 1: Nature of Lights Example 1 An electron is accelerated to a kinetic energy Ek of 2.5 MeV. (a) Determine its relativistic momentum, de Broglie wavelength, and speed. (b)…