Thread: switch statement / command line

Hi, I in desperate need of help. I have most of my functions in a program working, but in order to call them I need to use the command line arguments

In order to access a particular function like the create mode the user woul input

dataprog C filename.dat

so I try inputting argv[1] in the switch, but everything I try doesn't work

here is the code for main

int main(int argc, char *argv[])
{

if(argc !=3)
{
printf("Usage: dataprog <Mode C A or Q> <filename>\n");
exit(1);
}

switch (argv[1]) {
case 'A' : append_mode(char argv[]);
break;
case 'C' : create_mode(char argv[]);
break;
case 'Q' : query_mode(char argv[]);
break;
default: printf("Illegal code, enter (C)reate, (A)ppend or (Q)uery.\n");
}

return 0;
}

Your help would be very much appreciated

argv[1] is a pointer to the start of the second command line string... you just need to look at the value of the first character in the string, correct? Try de-referencing the pointer (*argv[1])...?

Try something like this

Code:

#include <stdio.h>

void create_file(char* fn);

int main(int argc, char* argv[])
{
     int i;
     for (i = 1; i < argc; ++i) {
             if (!strcmp(argv[i], "-c")) {
                    if (argv[++i]) 
                           create_file(argv[i]);
                    else
                           fprintf(stderr, "-c must have argument\n");
              }

              /* more code */
     }

     return 0;
}

Hi

Actually the argv[1] will be the starting address of the argv[1] string.

if you give argv[1] in the switch case that means you are checking with the address of argv[1], which would not satisfy your check, our purpose would be to check withthe content...

Please change switch as

switch(*argv[1])
{
}

It will work properly


All the best