Comp Sci How to debug an infinite loop in a C++ program using fork gymnastics?

[carl123]

This is what I did but I'm getting an infinite loop of the reversed string whenever I run the program. I don't know why

#include <stdio.h> 
#include <stdlib.h>
#include <string.h>
#include <unistd.h> /* for fork() and getpid() */
#include <sys/types.h>
#include <iostream>
using namespace std;
string result;
void print(string s, int index){
   pid_t pid;
   pid = fork();
   if(pid == 0){
       //child
       cout<<s[index];
       index--;
       print(s,index);
       exit(0);
   }
   else if (pid < 0){
       cout<<s[index];
       index--;
       print(s,index);
       exit(0);
   }
   else{
       cout<<s[index];
       index--;
       exit(0);
   }
}
int main(){
   string s;
   int length;
   cout<<"Enter string to invert\n";
   cin>>s;
   cout<<"Reverse String: \n";
   print(s,s.size()-1);
}

 

[Dr Transport]

looks like index decrements without bound...

 

[carl123]

looks like index decrements without bound...

Can you explain what you mean sorry?

 

[Dr Transport]

index-- has no lower bound, in other words how does it know when to stop when it gets to 0? I can't help you trace it because I do not have <unistd.h>...i.e. it isn't a part of Visual Studio 2015...