C program hangs after fork - c

Question

I have made the following program :
The aim is to make 5 child processes and have parent process send a string to each child process
to print. If I pass the argument xyz then this program prints xyz 2 times and then hangs.
Not sure why that is happening.
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
int main(int argc, char *argv[])
{
int num_processes = 5;
int pipefd[num_processes][2];
pid_t cpid;
char buf;
if (argc != 2)
{
fprintf(stderr, "Usage: %s <string>\n", argv[0]);
exit(EXIT_FAILURE);
}
for (int i = 0; i < num_processes; i++)
{
if (pipe(pipefd[i]) == -1)
{
perror("pipe");
exit(EXIT_FAILURE);
}
}
for (int i = 0; i < num_processes; i++)
{
cpid = fork();
if (cpid == -1)
{
perror("fork");
exit(EXIT_FAILURE);
}
if (cpid == 0)
{ /* Child reads from pipe */
close(pipefd[i][1]); /* Close unused write end */
while (read(pipefd[i][0], &buf, 1) > 0)
write(STDOUT_FILENO, &buf, 1);
write(STDOUT_FILENO, "\n", 1);
close(pipefd[i][0]);
}
else
{ /* Parent writes argv[1] to pipe */
close(pipefd[i][0]); /* Close unused read end */
write(pipefd[i][1], argv[1], strlen(argv[1]));
close(pipefd[i][1]); /* Reader will see EOF */
wait(NULL); /* Wait for child */
}
}
_exit(EXIT_SUCCESS);
}