Return the length of a string easily in C.

#include <stdio.h>
#include <stdlib.h>
 
int main (void) {
	char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
	int len_str; 
 
	// calculates length of string 
	len_str = sizeof(base64) / sizeof(base64[0]);
	printf("%d\n", len_str);
	return 0;
}

	if (argc > 1 and strncmp(argv[1], "3", BUF) == 0) {
		printf("\t\tCdrom drive information.\n");
 
 
//		kernel("/proc/sys/dev/cdrom/info", 5);
 
		strncpy(Args, "/proc/sys/dev/cdrom/info", 24);
		sprintf(buf, "cat %s\n", Args);
		fflush(stdout);
		system(buf);
 
	}

	char* myarg1 = argv[1];
	static char Args[256];
	char buf[256];
 
	if (!argc or !myarg1) {
		print_menu();
	}

enum { VERSION = 160 };
#define SYSINFO "Sysinfo version v%i.%i"
 
const char *p = "System Information Program";
char ver[128];
 
void print_menu()
{
	printf("\tSysinfo. %s\n\n", p);
 
	printf("1 - Kernel Information.\n2 - Memory & processes.\n");
	printf("3 - CDROM Information.\n4 - View list of sound cards.\n");
	printf("5 - View Real Time Clock Information.\n");
	printf("6 - View motherboard and BIOS information.\n");
	printf("7 - View information about your Xorg display.\n");
	printf("8 - View information about your IP addresses.\n");
 
	sprintf (ver, SYSINFO, VERSION / 100, VERSION % 100);
 
	printf("\n%s, by John Cartwright 2007.\nsysinfo comes with ", ver);
	printf("ABSOLUTELY NO WARRANTY. This\n is open source software,");
	printf("and you are welcome to \nredistribute it under certain ");
	printf("conditions as \noutlined in the GNU Public License.\n\n");
	exit(0);
}

		printf("\t\tXorg information.\n");
		Display *display;
		Screen *screen;
		display = XOpenDisplay(NULL);
		int count_screens = ScreenCount(display);
		printf("Total count screens: %d\n", count_screens);
		for (int i = 0; i < count_screens; ++i) {
			screen = ScreenOfDisplay(display, i);
			printf("\tScreen %d: %dX%d\n", i + 1, screen->width, screen->height);
		}
		XCloseDisplay(display);