How to fix loop not working using execv and forks - c++

Question

When running this program after the first iteration the program stops. This is because of execv function. What can I do so my loop still continues on until the user types quit.
I have tried creating a fork process before doing the execv in the child process but that does not work.
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
using namespace std;
int main(){
int pipefd[2];
int rs;
pid_t cpid;
pid_t cpid2;
rs = pipe(pipefd);
char* args1[256];
char* args2[256];
if (rs < 0){
perror("pipe");
exit(1);
}
char cmd1[256];
char cmd2[256];
char path1[10];
char path2[10];
while(true){
cout << "Command 1";
cin.getline(cmd1,256);
cout << "command 2";
cin.getline(cmd2,256);
if (strcmp(cmd1,"quit") == 0)
break;
if (strcmp(cmd2,"quit") == 0)
break;
char *token;
token = strtok(cmd1," ");
int i=0;
while(token != NULL){
args1[i] = token;
token = strtok(NULL, " ");
i++;
}
args1[i] = NULL;
token = strtok(cmd2," ");
i = 0;
while(token != NULL){
args2[i] = token;
token = strtok(NULL, " ");
i++;
}
args2[i] = NULL;
strcpy(path1,args1[0]);
strcpy(path2,args2[0]);
rs = fork();
if (rs < 0){
perror("Fork");
exit(1);
}
if (rs == 0){//child process
close(pipefd[1]);
close(0);
dup(pipefd[0]);
close(pipefd[0]);
rs = execvp(path2,args2);
if (rs < 0){
perror("execl");
exit(EXIT_FAILURE);
}
}
else{//PARENT PROCESS
close(pipefd[0]);
close(1);
dup(pipefd[1]);
close(pipefd[1]);
wait(&rs);
rs = execvp(path1,args1);
if (rs < 0){
perror("execl");
exit(EXIT_FAILURE);
}
}
};
return 0;
}
After outputting the answer the function should then ask the user for two more commands, This should go on until the user types in quit.

Answer 1

First of all exit(EXIT_FAILURE) is making your program exit.So remove it.
And you can put the possible exception creating code in try {} catch {} block.
In your case like this..
try{
rs = execvp(path1,args1);
if (rs < 0){
perror("execl");
//exit(EXIT_FAILURE);
}
}catch(int y){
continue;//here you can put your handling logic
}
By this you will get the desired output.