6-data-types/

6-data-types/CMakeLists.txt

@@ -0,0 +1,27 @@
+# Objects, size, precision, width, limits
+add_executable(size size.c)
+add_executable(precision precision.c)
+add_executable(int-limits int-limits.c)
+add_executable(exact-width exact-width.c)
+
+add_executable(unsigned unsigned.c)
+add_executable(for-unsigned for-unsigned.c)
+add_executable(sizet sizet.c)
+add_executable(timing-primes timing-primes.c)
+
+add_executable(char char.c)
+
+add_executable(unsinged-wrap unsigned-wrap.c)
+add_executable(unsigned-wrap-fix unsigned-wrap-fix.c)
+
+add_executable(implicit-conversion implicit-conversion.c)
+add_executable(integer-promotion integer-promotion.c)
+add_executable(explict-conversion explict-conversion.c)
+
+add_executable(float-limits float-limits.c)
+
+add_executable(sum-product sum-product.c)
+add_executable(loop loop.c)
+
+add_executable(compare compare.c)
+target_link_libraries(compare m)

6-data-types/README.md

@@ -0,0 +1,23 @@
+# 7-data-types
+
+## `int-limits.c`
+
+## `unsigned.c`
+
+## `timing.c`
+
+## `char.c`
+
+## `int-overflow.c`
+
+## `implicit-inversion.c`
+
+## `explicit-inversion.c`
+
+## `float-limits.c`
+
+## `sums.c`
+
+## `loop.c`
+
+## `compare.c`

6-data-types/char.c

@@ -0,0 +1,16 @@
+// Created by hfwei on 2024/10/30.
+
+#include <limits.h>
+#include <stdio.h>
+
+int main() {
+  printf("CHAR_MIN = %d\n", CHAR_MIN);
+  printf("CHAR_MAX = %d\n", CHAR_MAX);
+
+  char c = 150;
+  int i = 900;
+
+  printf("i / c = %d\n", i / c);
+
+  return 0;
+}

6-data-types/compare.c

@@ -0,0 +1,28 @@
+/**
+ * file: compare.c
+ *
+ * See https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
+ *
+ * Created by hfwei on 2022/11/10.
+ */
+
+#include <float.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+#define EPSILON 1e-5
+
+bool IsEqual(double x, double y);
+
+int main() {
+  printf("%d\n", IsEqual(DBL_MAX, DBL_MAX - 100));
+
+  printf("%.50f\n", DBL_MAX - (DBL_MAX - 100));
+
+  return 0;
+}
+
+bool IsEqual(double x, double y) {
+  return fabs(x - y) <= EPSILON;
+}

6-data-types/exact-width.c

@@ -0,0 +1,10 @@
+// Created by hfwei on 2024/10/31.
+
+#include <stdint.h>
+
+int main(void) {
+  int8_t small = -100;
+  int32_t large = 100000;
+
+  return 0;
+}

6-data-types/explict-conversion.c

@@ -0,0 +1,18 @@
+// Created by hfwei on 2024/10/30.
+
+#include <limits.h>
+#include <stdio.h>
+
+int main() {
+  double pi = 3.14159;
+
+  // below: obtain its fractional part
+  double fraction = pi - (int)pi;
+
+  int num = 100000000; // (9 digits)
+  printf("LLONG_MAX = %lld\n", LLONG_MAX);
+  long long llint = (long long)num * num;
+  printf("i = %lld\n", llint);
+
+  return 0;
+}

6-data-types/float-limits.c

@@ -0,0 +1,29 @@
+// Created by hfwei on 2024/10/30.
+
+#include <float.h>
+#include <stdio.h>
+
+int main() {
+  // float pi = 3.14F;
+
+  // 3.402823e+38
+  printf("FLT_MAX = %e\n", FLT_MAX);
+  // 1.175494e-38
+  printf("FLT_MIN = %e\n", FLT_MIN);
+  // 1.401298e-45
+  printf("FLT_TRUE_MIN = %e\n", FLT_TRUE_MIN);
+  // 1.192093e-07
+  printf("FLT_EPSILON = %e\n\n", FLT_EPSILON);
+
+  // %lf for scanf
+  // 1.797693e+308
+  printf("DBL_MAX = %e\n", DBL_MAX);
+  // 2.225074e-308
+  printf("DBL_MIN = %e\n", DBL_MIN);
+  // 4.940656e-324
+  printf("DBL_TRUE_MIN = %e\n", DBL_TRUE_MIN);
+  // 2.220446e-16
+  printf("DBL_EPSILON = %e\n\n", DBL_EPSILON);
+
+  return 0;
+}

6-data-types/for-unsigned.c

@@ -0,0 +1,14 @@
+// Created by hfwei on 2024/10/31.
+
+#include <stdio.h>
+#define LEN 100
+
+int main(void) {
+  int numbers[LEN] = {0};
+
+  for (unsigned int i = LEN; i >= 0; i--) {
+    printf("%u : %d\n", i, numbers[i]);
+  }
+
+  return 0;
+}

6-data-types/implicit-conversion.c

@@ -0,0 +1,35 @@
+// Created by hfwei on 2024/10/30.
+
+#include <limits.h>
+#include <stdio.h>
+
+int SquareInt(int num);
+double SquareDouble(double num);
+
+int main() {
+  // narrowing conversion (still in the range)
+  int i = 3.14159;
+
+  // out of the range: undefined behavior!!!
+  int j = UINT_MAX;
+
+  // arguments; narrowing conversion
+  double pi = 3.14;
+  SquareInt(pi);
+
+  // return value; narrowing conversion
+  int val = SquareDouble(pi);
+
+  // from int to float; narrowing conversion
+  int big = 1234567890;
+  float approx = big;
+
+  printf("big = %d\t approx = %f\t diff = %d\n", big, approx,
+         big - (int)approx);
+
+  return 0;
+}
+
+int SquareInt(int num) { return num * num; }
+
+double SquareDouble(double num) { return num * num; }

6-data-types/int-limits.c

@@ -0,0 +1,35 @@
+// Created by hfwei on 2024/10/30.
+// Run on Windows and Linux
+
+#include <limits.h>
+#include <stdio.h>
+
+int main() {
+  // INT_MIN = -2147483648
+  // INT_MAX = 2147483647 (10 digits)
+  printf("INT_MIN = %d\n", INT_MIN);
+  printf("INT_MAX = %d\n\n", INT_MAX);
+
+  // printf("UINT_MIN = %u\n", 0U);
+  // printf("UINT_MAX = %u\n\n", UINT_MAX);
+
+  printf("LONG_MIN = %ld\n", LONG_MIN);
+  printf("LONG_MAX = %ld\n\n", LONG_MAX);
+
+  // printf("ULONG_MIN = %lu\n", 0UL);
+  // printf("ULONG_MAX = %lu\n\n", ULONG_MAX);
+
+  // long long int: >= 64 bits
+
+  // LLONG_MIN = -9223372036854775808
+  // LLONG_MAX = 9223372036854775807 (19 digits)
+  printf("LLONG_MIN = %lld\n", LLONG_MIN);
+  printf("LLONG_MAX = %lld\n\n", LLONG_MAX);
+
+  // printf("ULONG_LONG_MIN = %llu\n", 0ULL);
+  // printf("ULONG_LONG_MAX = %llu\n\n", ULONG_LONG_MAX);
+  //
+  // printf("ULLONG_MAX = %llu\n\n", ULLONG_MAX);
+
+  return 0;
+}

6-data-types/integer-promotion.c

@@ -0,0 +1,13 @@
+// Created by hfwei on 2024/10/31.
+
+#include <stdio.h>
+
+int main(void) {
+  signed char left = 100;
+  signed char mid = 3;
+  signed char right = 4;
+
+  signed char result = left * mid / right;
+
+  printf("result = %d\n", result);
+}

6-data-types/loop.c

@@ -0,0 +1,17 @@
+// Created by hengxin on 2024/10/30.
+
+#include <stdio.h>
+
+int main() {
+  /**
+   * Do not use a counter of type float/double,
+   * although it works on some platforms.
+   *
+   * 0.1 cannot be exactly represented in machines.
+   */
+  for (double x = 0.1; x <= 1.0; x += 0.1) {
+    printf("%.20f\n", x);
+  }
+
+  return 0;
+}

6-data-types/precision.c

@@ -0,0 +1,23 @@
+// Created by hfwei on 2024/10/31.
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+unsigned int pow2(unsigned int exp);
+
+int main(void) {
+  unsigned int exp = 30;
+
+  unsigned int pow = pow2(exp);
+  printf("2^%d = %d\n", exp, pow);
+}
+
+unsigned int pow2(unsigned int exp) {
+  if (exp >= sizeof(unsigned int) * CHAR_BIT) {
+    printf("Exp is too large!\n");
+    exit(1);
+  }
+
+  return 1 << exp;
+}