add changes to sqlite_ex and some new files

cat_v1.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+
+void filecopy(FILE *, FILE *);
+
+int main(int argc, char *argv[]) {
+  FILE *file_p;
+
+  if (argc == 1)
+    filecopy(stdin, stdout);
+  else
+    while (--argc > 0)
+      if ((file_p = fopen(*++argv, "r")) == NULL) {
+        printf("cat: can't open: %s\n", *argv);
+        return 1;
+      } else {
+        filecopy(file_p, stdout);
+        fclose(file_p);
+      }
+  return 0;
+}
+
+void filecopy(FILE* in_file_p, FILE* out_file_p) {
+  int ch;
+
+  while((ch = getc(in_file_p)) != EOF)
+    putc(ch, out_file_p);
+}

cat_v2.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void filecopy(FILE *, FILE *);
+
+int main(int argc, char *argv[]) {
+  FILE *file_p;
+  char *prog_name = argv[0];
+
+  if (argc == 1)
+    filecopy(stdin, stdout);
+  else
+    while (--argc > 0)
+      if ((file_p = fopen(*++argv, "r")) == NULL) {
+        fprintf(stderr, "%s: can't open: %s\n", prog_name, *argv);
+        exit(1);
+      } else {
+        filecopy(file_p, stdout);
+        fclose(file_p);
+      }
+  if (ferror(stdout)) {
+    fprintf(stderr, "%s: error writing stdout\n", prog_name);
+    exit(2);
+  }
+  exit(0);
+}
+
+void filecopy(FILE *in_file_p, FILE *out_file_p) {
+  int ch;
+
+  while ((ch = getc(in_file_p)) != EOF)
+    putc(ch, out_file_p);
+}

minprintf.c

@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include <stdarg.h>
+
+void minprintf(char *fmt, ...) {
+  va_list arg_pointer;
+  char *p, *sval;
+  int ival;
+  double dval;
+
+  va_start(arg_pointer, fmt);
+  for (p = fmt; *p; p++) {
+    if (*p != '%') {
+      putchar(*p);
+      continue;
+    }
+    switch(*++p) {
+      case 'd':
+        ival = va_arg(arg_pointer, int);
+        printf("%d", ival);
+        break;
+      case 'f':
+        dval = va_arg(arg_pointer, double);
+        printf("%f", dval);
+        break;
+      case 's':
+        for(sval = va_arg(arg_pointer, char*); *sval; sval++)
+          putchar(*sval);
+        break;
+      default:
+        putchar(*p);
+        break;
+    }
+  }
+  va_end(arg_pointer);
+}

rudimentary_calc.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int main() {
+  double sum = 0, val;
+
+  while(scanf("%lf", &val) == 1)
+    printf("\t%.2f\n", sum += val);
+  return 0;
+}

sqlite_ex.c

@@ -16,8 +16,38 @@ int main(int argc, char **argv) {
     return 1;
   }
 
-  if (argc == 2 && !strcmp(argv[1], "-t")) {
-    sqlite_list_tables(db);
+  if (argc == 2) {
+    if (!strcmp(argv[1], "-t")) {
+      sqlite_list_tables(db);
+    } else if (!strcmp(argv[1], "-i")) {
+      char *ms[] = {"gas", "water", "electricity"};
+      float ms_num[] = {0, 0, 0};
+
+      for (int i = 0; i < 3; ++i) {
+        printf("Enter %s measurement: ", ms[i]);
+        scanf("%f", &ms_num[i]);
+      }
+
+      sqlite3_stmt *st;
+      respCode = sqlite3_prepare_v2(db, INSERT_MEASUREMENT, -1, &st, NULL);
+      if (respCode != SQLITE_OK) {
+        fprintf(stderr, "Prepared statement error: %d\n", respCode);
+      }
+      sqlite3_bind_double(st, 1, ms_num[0]);
+      sqlite3_bind_double(st, 2, ms_num[1]);
+      sqlite3_bind_double(st, 3, ms_num[2]);
+      respCode = sqlite3_step(st);
+      if (respCode != SQLITE_DONE) {
+        fprintf(stderr, "Error while executing statement: %d", respCode);
+      }
+
+      respCode = sqlite3_finalize(st);
+      if (respCode != SQLITE_OK) {
+        fprintf(stderr, "Prepared statement finalization error: %d\n",
+                respCode);
+        sqlite3_free(zErrMsg);
+      }
+    }
   } else {
     sqlite_exec_query(SELECT_COUNT_MEAS, count_measurements);
     measurements = malloc(sizeof(meas) * meas_count);
@@ -145,12 +175,28 @@ int dates_same(Datetime *dt1, Datetime *dt2) {
 }
 
 double communal_difference(meas *m_now, meas *m_twnth) {
-  double gas_diff = m_now->gas - m_twnth->gas;
-  double water_diff = m_now->water - m_twnth->water;
-  double electricity_diff = m_now->electricity - m_twnth->electricity;
+  double gas_diff = (int)m_now->gas - (int)m_twnth->gas;
+  double water_diff = (int)m_now->water - (int)m_twnth->water;
+  double electricity_diff = (int)m_now->electricity - (int)m_twnth->electricity;
 
-  return gas_diff * costs.gas_c + water_diff * costs.water_c +
-         electricity_diff * costs.electricity_c + costs.housing_c;
+  double gas_total = gas_diff * costs.gas_c;
+  double water_total = water_diff * costs.water_c;
+  double electricity_total = electricity_diff * costs.electricity_c;
+
+  printf(CALCULATION_FORMAT, "gas", (int)m_now->gas, (int)m_twnth->gas,
+         gas_diff, costs.gas_c, gas_total);
+  printf(CALCULATION_FORMAT, "water", (int)m_now->water, (int)m_twnth->water,
+         water_diff, costs.water_c, water_total);
+  printf(CALCULATION_FORMAT "\n", "electricity", (int)m_now->electricity,
+         (int)m_twnth->electricity, electricity_diff, costs.electricity_c,
+         electricity_total);
+
+  double grand_total =
+      gas_total + water_total + electricity_total + costs.housing_c;
+  printf("%.2f + %.2f + %.2f + %.2f = %.2f\n", gas_total, water_total,
+         electricity_total, costs.housing_c, grand_total);
+
+  return grand_total;
 }
 
 void print_measurements() {

sqlite_ex.h

@@ -11,6 +11,8 @@
 #define SELECT_ALL_TABLES "select * from sqlite_schema where type = 'table';"
 #define SELECT_TWNTH_DAY "select * from twnth_day;"
 #define SELECT_CURRENT_COSTS "select * from costs where id = ?;"
+#define INSERT_MEASUREMENT "insert into measurements (gas, water, electricity, costs) values (?, ?, ?, 1);"
+#define CALCULATION_FORMAT "%s: %d - %d = %f * %f = %f\n"
 #define STR_SIZE 11
 
 typedef struct tm Datetime;