How to use nested Switch with commandline arguments? - c

Question

I have my switch case and statements inside my main function as follows:
int main(int argc, char *argv[])
{
int c;
while((c = getopt(argc,argv,"ABS"))!=-1)
{
switch(c)
{
case 'A':
flag = 0;
printf("open the port\n");
struct can_frame frame_rd;
open_port("vcan0");
printf("vcan0 port is opened");
fflush(stdout);
create_file();
while(1)
{
read_port(&frame_rd);
}
break;
case 'B':
flag = 1;
printf("open the port\n");
open_port("vcan0");
printf("vcan0 port is opened");
fflush(stdout);
create_binfile();
while(1)
{
read_port(&frame_rd);
}
break;
}
}
Now I want to make use of nested switch when user passes an argument -S inside the case A can i do it as follows? Is the following procedure correct?
int main(int argc, char *argv[])
{
int c;
while((c = getopt(argc,argv,"ABS"))!=-1)
{
switch(c)
{
case 'A':
switch(c)
{
case 'S':
size = 100;
break;
}
flag = 0;
printf("open the port\n");
struct can_frame frame_rd;
open_port("vcan0");
printf("vcan0 port is opened");
fflush(stdout);
create_file();
while(1)
{
read_port(&frame_rd);
}
break;
case 'B':
flag = 1;
printf("open the port\n");
open_port("vcan0");
printf("vcan0 port is opened");
fflush(stdout);
create_binfile();
while(1)
{
read_port(&frame_rd);
}
break;
}
}
In the above code can I use same switch(c) for the nested case also , is the usage of nested switch correct?Thanks in advance.

Answer 1

No, within the outer swich case 'A', variable c can be thought of as constant, therefore your nested switch will not find a case to match and does not have a default case.
If you know your arguments are in a particular order, you can address them directly e.g. argv[1] and argv[2] for the first and second arguments.