Implementing a pipe functionality in shell. In C - c

Question

In the provided code below, the redirection methods work, however i've been having trouble with getting the pipe function to work.
This is how I'm viewing the flow of the code (at least for the pipe) and correct me if I'm wrong: When the array containing the users command (argv[]) is being traversed and checked for pipe declarations ("|"), for however many ("|") it detects, it will do that number of processes (processes++). It will then clear out the user command for future use, and go through the checks to continue the program.
I will also say I only have processes declared and iterated once, and I wasn't sure if I return it or implement it somewhere else.
Here is what I have so far:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <fcntl.h>
int main()
{
char *path, //shell system path indicator
*argv[20], //user command
buf[80], //will pass user command to argv
n, //user input
*p; //points to buffer
int m, // represents size
status, // checks if ant conditions violate the while loop
inword,
check,
continu;
while(1) //an infinite loop to keep the shell running
{
inword = 0; //set as false
p = buf; // p represents buffer
m = 0; //size of argv array
continu = 0; //set as false
printf("\nshhh> "); //display of shell prompt
while ((n = getchar()) != '\n' || continu) //while user input is not end of line OR
{
if (n == ' ') // if input is a space
{
if (inword) // if 0
{
inword = 0; // remains 0
*p++ = 0; //increment to next position in buffer[80]
}
}
else if (n == '\n') //if user input == end of line
continu = 0; // continue is 0 which breaks the while loop
else if (n == '\\' && !inword) // if user input == '\\' and inword is not 0
continu = 1; // continu is changed to 1 and you stay in while loop
else
{
if (!inword)
{
inword = 1;
argv[m++] = p; //next iteration of user command contains buffer
*p++ = n; //next slot in buffer contains user input
}
else
*p++ = n; //next slot in buffer contains user input
}
}
*p++ = 0; // next slot in buffer is 0
argv[m] = 0; //clear user command
if (strcmp(argv[0],"exit") == 0) //if user command is exit
exit (0); //end program
int processes = 0,
gate1,
gate2,
pipe_end[2],
pipe_id;
if (fork() == 0)// passing command to array
{
for(int iteratr = 0; argv[iteratr] != 0; iteratr++)
{
if(strcmp("|", argv[iteratr]) == 0)// pipe configuration
{
processes++;
argv[iteratr] = 0; //empty array for next user command
pipe(pipe_end);
if (pipe(pipe_end)==-1) // Check for pipe functionality
{
perror("Pipe Failed");
return 1;
}
pipe_id = fork();
if (pipe_id < 0) //Check for fork functionality
{
printf("Fork failed");
return 1;
}
else if(pipe_id == 0)//Child
{
close(1); //close stdout
dup(pipe_end[1]); //copy stdout
close(pipe_end[0]); //close read in
close(pipe_end[1]); //close write out
execvp(argv[0], argv); //execute "pre" read in
}
else //Parent
{
close(0); //close stdin
dup(pipe_end[0]); //copy stdin
close(pipe_end[0]); //close read in
close(pipe_end[1]); //close write out
execvp(argv[0], argv); //execute "sort" read in
}
}
if(strcmp("<", argv[iteratr]) == 0)// Input redirect
{
gate1 = open("input.txt", O_RDONLY);
close(0);
dup(gate1);
close(gate1);
argv[iteratr] = 0;
execvp(argv[0], argv);
}
if(strcmp(">", argv[iteratr]) == 0) // Output redirect
{
gate2 = creat("output.txt", 0750);
close(1);
dup(gate2);
close(gate2);
argv[iteratr] = 0;
execvp(argv[0], argv);
}
}
execvp(argv[0], argv);
printf(" didn't exec \n ");
check = wait(&status);
}
wait(&status); //check
}
return 0;
}