Rare behaviour in command line arguments - c++

Question

I am trying to write a program in cpp using maps...
My goal is to allow * alone when we pass via comand line argument
And i have to restrict the characters coming along with * (ie)abc and abc
int main(int argc,char *argv[])
{
prinf("%s\n",argv[1]);
char str[256] = "";
int length;
strcpy(str,argv[1]);
length = strlen(str);
if((str[0] = '*' )&& (length == 1))
printf("success\n");
else
printf("failure");
return 0;
}
when i run this program ,getting the following output
$ ./exec *
$ 1
$ failure
argv[1] = 1(printing 1 instead of *)
failure because of not getting * as input argument,it results in failure.
Could someone help me to solve this issue?

Answer 1

Items on the command line are processed by the shell.
In the shell, the * performs a glob operation
In general, a glob operator, when standing alone, will result in a list of all the files in the current directory.

Answer 2

The character * has a special meaning in most shells. Your shell expands it to the files in the current directory resulting in a completely different arguments than the one you intended.
To avoid this, you can do:
$ ./exec "*"
or
$ ./exec '*'
If your shell is bash, then you can also turn off the globbing expansion with:
$ set -o noglob
or
$ set -f
but I would suggest the former options (above) as it's "minimal" and doesn't affect your shell's default behaviour otherwise.