Feedback on ex0.* and ex1.*

ex0.2/gen_rand_explicit.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python3
+
+import numpy as np
+import sys
+
+N = 1e6
+
+if len(sys.argv) > 1:
+    N = float(sys.argv[1])
+
+for _ in range(int(N)):
+    print( np.random.rand(1) )

ex0.2/results.txt

@@ -1,4 +1,10 @@
-Running `time ./gen_rand.py "1e9"` gives 
+Running `time ./gen_rand.py "1e6"` gives 
 
-real 0m13.803s
+real	0m0.237s
-user 0m8.874s
+user	0m0.160s
+
+Contrast this to the following:
+Running `time ./gen_rand_explicit.py "1e6"` gives
+
+real	2m11.564s
+user	2m1.950s

ex1.2/string_analyzer.cpp

@@ -19,15 +19,15 @@ int main() {
 	unsigned int chars_capital = 0, chars_lower = 0, chars_digits = 0, chars_other = 0;
 	while ( *ptr != 0 )
 	{
-		if ( *ptr >= int('A') && *ptr <= int('Z') )
+		if ( *ptr >= 'A' && *ptr <= 'Z' )
 		{
 			++chars_capital;
 		}
-		else if ( *ptr >= int('a') && *ptr <= int('z') )
+		else if ( *ptr >= 'a' && *ptr <= 'z' )
 		{
 			++chars_lower;
 		}
-		else if ( *ptr >= int('0') && *ptr <= int('9') )
+		else if ( *ptr >= '0' && *ptr <= '9' )
 		{
 			++chars_digits;
 		}

ex1.3/join_strings.cpp

@@ -39,7 +39,9 @@ char* join(const char* str1 , const char* str2)
 
 char* joinb(const char* str1 , const char* str2)
 {
-	int size = strlen(str1) + strlen(str2) + 1;
+	// size should be 2 more than required for the strlens to 
+	// incorporate the space and the null byte
+	int size = strlen(str1) + strlen(str2) + 2;
 
 	char* new_str = new char[size];
 	*new_str =  0;

ex1.4/leak_memory.cpp

@@ -15,12 +15,25 @@
 
 #define MEMORY_SIZE_IN_CHARS G
 
+void make_throwaway_ptrs(int leak_size ) {
+	for ( int i = 0; i < leak_size ; i++)
+	{
+		char* throwaway_ptr = new char;
+	}
+
+	// oops, we are not returning the pointers
+	// this means it goes out of scope when the function ends
+}
+
+
 int main() {
-	char* throwaway_ptr = new char[MEMORY_SIZE_IN_CHARS];
+	make_throwaway_ptrs(MEMORY_SIZE_IN_CHARS);
 
 	std::cout << "We leaked " << MEMORY_SIZE_IN_CHARS * sizeof " " << " bits" << std::endl;
 
+
+	std::cout << "Ready to kill the process? (press Enter)" << std::endl;
+	std::cin.ignore();
 	return 0;
 }
-	
 

ex1.5/base32.cpp

@@ -23,10 +23,10 @@
 #include <iostream>
 #include <cmath>
 
-#define VERBOSE false
+#define VERBOSE true
 
-char b32_lookup_table[] = "ABCDEFGHIJKLMNOPQRSTUV";
+char b32_lookup_table[] = "0123456789ABCDEFGHIJKLMNOPQRSTUV";
-int base = 8;
+int base = 32;
 
 int main() {
 	//a
@@ -75,7 +75,7 @@ int main() {
 		digits[digit_num] = number & lsb_bitmask;
 		
 		// Shift off the bits we have put in to the array
-		number = ( number >> bits_in_char );
+		number >>= bits_in_char;
 
 		++digit_num;
 	}
@@ -91,14 +91,7 @@ int main() {
 	// Loop the other way so the first digit we get out is MSB
 	while ( digit_num >= 0 ) 
 	{
-		if ( digits[digit_num] < 10 )
+		std::cout << b32_lookup_table[digits[digit_num]];
-		{
-			std::cout << digits[digit_num];
-		}
-		else 
-		{
-			std::cout << b32_lookup_table[digits[digit_num] - 10];
-		}
 
 		digit_num--;
 	}