It kinda works right now

cal.c

@@ -0,0 +1,244 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+typedef enum months{Jan = 0, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec} months;
+int month_key[12] = {1, 4, 4, 0, 2, 5, 0, 3, 6, 1, 4, 6};
+char * prog_name;
+
+int is_lyear(int);
+int get_first_day(int, months);
+int get_last_day(int, months);
+char * get_month_string(months);
+int stoi_mini(char *);
+
+int main(int argc, char * argv[]) {
+  /*
+    printf("\033[30;47mBlack on White\033[0m\n");
+    printf("\033[37;40mWhite on Black\033[0m\n");
+  */
+  prog_name = argv[0];
+
+  
+
+  int calendar[7][6];
+  months month;
+  int year;
+  int cur_day = 0;
+
+  if(argc == 1) {
+    time_t t = time(0);
+    struct tm* cur_date = localtime(&t);
+    month = cur_date->tm_mon;
+    /* 
+       Note to future me:
+       Years are given relative to 1900.
+       That's why it's tm_year + 1900.
+       Have a nice day! ;D
+       -Kat
+    */
+    year = cur_date->tm_year + 1900;
+    cur_day = cur_date->tm_mday;
+  }
+  else if(argc == 2) {
+    fprintf(stderr, "%s: feature currently not implemented\n", prog_name);
+    exit(127);
+  }
+  else if(argc == 3) {
+    month = stoi_mini(argv[1]) - 1;
+    year = stoi_mini(argv[2]);
+  }
+
+  if(year < 1) {
+    fprintf(stderr, "%s: invalid year: use positive integer\n", prog_name);
+    exit(1);
+  }
+
+  char * month_string = get_month_string(month);
+
+  int d = 1;
+  int i, j;
+  for(i = 0; i < 6; i++) {
+    if(i == 0) {
+      for(j = 0; j < get_first_day(year, month); j++) {
+	calendar[j][i] = 0;
+      }
+    }
+    for(j = (i == 0) ? get_first_day(year, month) : 0; j < 7; j++) {
+      calendar[j][i] = d;
+      d++;
+    }
+  }
+
+  printf("%s %d\n", month_string, year);
+  printf("Su Mo Tu We Th Fr Sa\n");
+  for(i = 0; i < 6; i++) {
+    for(j = 0; j < 7; j++) {
+      if(calendar[j][i] == 0) {
+	printf("   ");
+      }
+      else if(calendar[j][i] > get_last_day(year, month)) {
+	i = 6; j = 7;
+	break;
+      }
+      else {
+	if(calendar[j][i] == cur_day && cur_day != 0) {
+	  if(isatty(fileno(stdout))) {
+	    printf("\033[7m%2d\033[0m ", calendar[j][i]);
+	  }
+	  else {
+	    printf("%2d ", calendar[j][i]);
+	  }
+	}
+	else {
+	  printf("%2d ", calendar[j][i]);
+	}
+      }
+    }
+    printf("\n");
+  }
+}
+
+/* 
+   l for leap!
+   -Kat
+ */
+int is_lyear(int year) {
+  if(year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) {
+    return 1;
+  }
+  else {
+    return 0;
+  }
+}
+
+int get_first_day(int year, months month) {
+  int calc = year % 100;
+  calc /= 4;
+  calc += 1;
+  calc += month_key[month];
+  if(is_lyear(year)) {
+    calc -= 1;
+  }
+  if(year > 1752) {
+    int temp = year / 100;
+    calc += (temp == 19) ? 0 :
+      (temp == 20) ? 6 :
+      (temp == 17) ? 4 : 2;
+  }
+  else {
+    int temp = year / 100;
+    calc += (18 - temp);
+  }
+  calc += (year % 100);
+  calc %= 7;
+  calc -= 1;
+  return calc;
+}
+
+char * get_month_string(months month) {
+  if(month == Jan) {
+    return "January";
+  }
+  else if(month == Feb) {
+    return "February";
+  }
+  else if(month == Mar) {
+    return "March";
+  }
+  else if(month == Apr) {
+    return "April";
+  }
+  else if(month == May) {
+    return "May";
+  }
+  else if(month == Jun) {
+    return "June";
+  }
+  else if(month == Jul) {
+    return "July";
+  }
+  else if(month == Aug) {
+    return "August";
+  }
+  else if(month == Sep) {
+    return "September";
+  }
+  else if(month == Oct) {
+    return "October";
+  }
+  else if(month == Nov) {
+    return "November";
+  }
+  else if(month == Dec) {
+    return "December";
+  }
+  else {
+    fprintf(stderr, "%s: invalid month passed in: use 1-12\n", prog_name);
+    exit(1);
+  }
+}
+
+
+int get_last_day(int year, months month) {
+  if(month == Jan) {
+    return 31;
+  }
+  else if(month == Feb) {
+    return is_lyear(year) ? 29 : 28;
+  }
+  else if(month == Mar) {
+    return 31;
+  }
+  else if(month == Apr) {
+    return 30;
+  }
+  else if(month == May) {
+    return 31;
+  }
+  else if(month == Jun) {
+    return 30;
+  }
+  else if(month == Jul) {
+    return 31;
+  }
+  else if(month == Aug) {
+    return 31;
+  }
+  else if(month == Sep) {
+    return 30;
+  }
+  else if(month == Oct) {
+    return 31;
+  }
+  else if(month == Nov) {
+    return 30;
+  }
+  else if(month == Dec) {
+    return 31;
+  }
+}
+
+int stoi_mini(char * str) {
+  int i, str_int = 0;
+
+  for(i = 0; str[i] != '\0' && str[i] != ','; i++) {
+    str_int *= 10;
+    switch(str[i]) {
+      case '0': str_int += 0; break;
+      case '1': str_int += 1; break;
+      case '2': str_int += 2; break;
+      case '3': str_int += 3; break;
+      case '4': str_int += 4; break;
+      case '5': str_int += 5; break;
+      case '6': str_int += 6; break;
+      case '7': str_int += 7; break;
+      case '8': str_int += 8; break;
+      case '9': str_int += 9; break;
+      default: return -1;
+    }
+  }
+
+  return str_int;
+}