Question

I get the following errors when I type the code

#include <iostream>
#include <string.h>
#include <bitset>
#include <math.h>
#define IS_INTEGRAL(T) typename std::enable_if< std::is_integral<T>::value >::type* = 0
using namespace std;
 
 
template<class T>
std::string inttobits1(T byte, IS_INTEGRAL(T))
{
        std::bitset<sizeof(T)* CHAR_BIT> bs(byte);
        return bs.to_string();
}
 
int bitstoint1(string bits)
{
        int value;
        for (int x = 0, y = bits.length() - 1;x < 8 && x < bits.length();x++)
        {
                int val = atoi(bits.substr(y, 1).c_str());
                value += (int)val * pow(2, x);
        }
        return value;
}
void getlikeyvoltages1(int pinvalue)
{
        //voltages used by OUSB range 0 to 5
        int probability = (int)pinvalue / 255;//this is the likely voltage that can be generated when it's value is pinvalue
        cout << "Votage produced by OUSB when the voltage is " << pinvalue << " = " << probability << endl;
}
void readpotentiometer1()
{
        unsigned char byte = 0x08;//mybyte
        string bits = inttobits1(byte);
        cout << "bits: " << bits << endl;//the bits read
 
        getlikeyvoltages1(bitstoint1(bits));
}
 
void readousb1()
{
        FILE* fpipe;   char command[] = "ousb io PINC";  // Read the switch state.   
        char line[256];
        if (!(fpipe = (FILE*)popen(command, "r"))) {
                // error if fpipe returns NULL       
                perror("Problems with pipe");
                exit(1);
        }
        while (fgets(line, sizeof line, fpipe)) {
                //divide by 4
                int val = atoi(line);
                val = val >> 2;//divide by 4
                printf("%d\n", val);    //the current value
        }
        pclose(fpipe);
 
 
}
int main(int argc, char** argv) {
 
        while (1)
        {
                readousb1();
                string s;
                cin >> s; //pause the program
        }
 
 
        return 0;
}

Error (active)   E0020   identifier "pclose" is undefined   LabPrac2020   
Error (active)   E0020   identifier "popen" is undefined   LabPrac2020   
Warning   C6001   Using uninitialized memory 'value'.   LabPrac2020   
Warning   C4018   '<': signed/unsigned mismatch   LabPrac2020
Warning   C4244   '+=': conversion from 'double' to 'int', possible loss of data      
Error   C3861   'popen': identifier not found
Error   C3861   'pclose': identifier not found   

Answer 1

it seem the eroor is because you have not included the apropriate header files .

Just include this header file and the code will run.

#include<bits/stdc++.h>

#include <iostream>
#include <string.h>
#include <bitset>
#include <math.h>

//include this header file
#include<bits/stdc++.h> 


#define IS_INTEGRAL(T) typename std::enable_if< std::is_integral<T>::value >::type* = 0
using namespace std;
 
 
template<class T>
std::string inttobits1(T byte, IS_INTEGRAL(T))
{
        std::bitset<sizeof(T)* CHAR_BIT> bs(byte);
        return bs.to_string();
}
 
int bitstoint1(string bits)
{
        int value;
        for (int x = 0, y = bits.length() - 1;x < 8 && x < bits.length();x++)
        {
                int val = atoi(bits.substr(y, 1).c_str());
                value += (int)val * pow(2, x);
        }
        return value;
}
void getlikeyvoltages1(int pinvalue)
{
        //voltages used by OUSB range 0 to 5
        int probability = (int)pinvalue / 255;//this is the likely voltage that can be generated when it's value is pinvalue
        cout << "Votage produced by OUSB when the voltage is " << pinvalue << " = " << probability << endl;
}
void readpotentiometer1()
{
        unsigned char byte = 0x08;//mybyte
        string bits = inttobits1(byte);
        cout << "bits: " << bits << endl;//the bits read
 
        getlikeyvoltages1(bitstoint1(bits));
}
 
void readousb1()
{
        FILE* fpipe;   char command[] = "ousb io PINC";  // Read the switch state.   
        char line[256];
        if (!(fpipe = (FILE*)popen(command, "r"))) {
                // error if fpipe returns NULL       
                perror("Problems with pipe");
                exit(1);
        }
        while (fgets(line, sizeof line, fpipe)) {
                //divide by 4
                int val = atoi(line);
                val = val >> 2;//divide by 4
                printf("%d\n", val);    //the current value
        }
        pclose(fpipe);
 
 
}
int main(int argc, char** argv) {
 
        while (1)
        {
                readousb1();
                string s;
                cin >> s; //pause the program
        }
 
 
        return 0;
}