Third process “wc” won't work

Question

I'm currently having a problem with the third process because it wont work every time when I run the program. And suggestions with the exit() part because is printing multiple child process! Any suggestions?

I would really APPRECIATE it a lot!

main(){
    pid_t son;
    int i;  
    for (i=0; i<3; i++){
        switch (i){
            case 0:
            son = fork();
                if (son<0){
                    fprintf(stderr, "Fork failed!");
                    //exit(-1);
                }else if (son == 0){
                    execlp("/bin/cat", "cat", "wctrial.txt", NULL);
                }else{
                wait(NULL);
                printf("Child process completed!");
                //exit(0);
                }
            case 1:
            son = fork();
                if (son<0){
                    fprintf(stderr, "Fork failed!");
                    //exit(-1);
                }else if (son == 0){
                    execlp("/bin/mkdir", "mkdir", "mydirectory", NULL);
                }else{
                wait(NULL);
                printf("Child process completed!");
                //exit(0);
                }
            case 2:
            son = fork();
                if (son<0){
                    fprintf(stderr, "Fork failed!");
                    //exit(-1);
                }else if (son == 0){
                    execlp("/bin/wc","wc","wctrial.txt", NULL);
                }else{
                wait(NULL);
                printf("Child process completed!");
                //exit(0);
         }
    }
}

Answer 1

At least I don't see the break at the end of the each case .

In the case of 0 the program will run through all of your case s.

Answer 2

Actually break is the problem that if case 1 execute then 2,3 also will.( but this is not problem that wc not working )

Why wc is not working ?

Because of path of wc command!

In your system path for wc may not is: "/bin/wc"

Search tha path of wc command in your system like:

:~$ whereis wc
wc: /usr/bin/wc   

and change

 execlp("/bin/wc","wc","wctrial.txt", NULL);
           ^ 

as

 execlp("/usr/bin/wc","wc","wctrial.txt", NULL);
          ^ 
          // actually not exactly this but one that appears in your system. 

Give it a try!!

Answer 3

Below are my suggestion ,

1st) suggestion would be the clean-up of child process once it is done, as below,

 }else if (son == 0){
        execlp("/bin/mkdir", "mkdir", "mydirectory", NULL);
        _exit(0);
 }

2nd) do break after each switch statement

3rd) and also validate the path of executable by using "whereis" command before feeding into execlp routine.