#include <iostream> #include <fstream> #include <string.h> #include <sys/types.h

Question

#include <iostream>
#include <fstream>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
using namespace std;
int main(int argc, char const *argv[])
{
int pfd[2];
pipe(pfd);
char op = 'y';
char cmdn1[10][20] = {0}; // saparate it
char cmdn2[10][20] = {0}; // saparate it
char * argv1[10] ; // give it to argv
char * argv2[10] ; // give it to argv
int i , j = 0 , k = 0;
char a[20]={0};
int wordc1 = 0;
int wordc2 = 0;
string quit;
while (1)
{
string string1, string2;
cout << "enter first string ";
getline(cin, string1);
cout << "enter second string ";
getline(cin, string2);
for( i =0 ; i<10;i++)
argv1[i] = NULL; // in the starting null all pointer
k = 0, j = 0 , i = 0;
for(i=0;i <= string1.size() ; i++)
{
if(string1[i] == ' ' || string1[i] == '') // saparate command
{
a[j] = '';
strcpy(cmdn1[k++],a);
argv1[k-1] = cmdn1[k-1]; // allocate each saparate argument to argv
j = 0;
wordc1++;
memset(a,0,sizeof(a));
}
else
a[j++] = string1[i];
}
for( i =0 ; i<10;i++)
argv2[i] = NULL; // in the starting null all pointer
k = 0, j = 0 , i = 0;
for(i=0;i <= string2.size() ; i++)
{
if(string2[i] == ' ' || string2[i] == '') // saparate command
{
a[j] = '';
strcpy(cmdn2[k++],a);
argv2[k-1] = cmdn2[k-1]; // allocate each saparate argument to argv
wordc2++;
j = 0;
memset(a,0,sizeof(a));
}
else
a[j++] = string2[i];
}
if (fork() == 0)
{
// child gets here and handles "grep Villanova"
// replace standard input with input part of pipe
dup2(pfd[0], 0);
// close unused hald of pipe
close(pfd[1]);
// execute grep
execvp(argv2[0], argv2);
}
else
{
// parent gets here and handles "cat scores"
// replace standard output with output part of pipe
dup2(pfd[1], 1);
// close unused unput half of pipe
close(pfd[0]);
// execute cat
execvp(argv1[0], argv1);
}
cin.clear();
cin.ignore(255,' ');
cout << "Do you want to quit (quit/no)? "; //this part not working .
cin >> quit;
if(quit=="quit")
break;
}
}

Would like the program to re-ask for first and second string if "quit" is never the input, Please help

Explanation / Answer

There is no need for

cin.clear()
cin.ignore(255,' ')

Rest of the code is fine.

Also instead of while(1) we can have while(quit[0] != 'q') . Also initialize quit as "start".

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