add some tests

tests/const_char.cc

+#include <string.h>
+
+// http://www.cpptalk.net/invalid-conversion-from-char-to-const-char-vt13716.html
+
+main(int argc, char **argv)
+{
+	char **t1;
+	const char **t2;
+	const char **t3 = new const char *[10]; // t3 - 土佑勺 账邻猎盘攀 瘟 const char*
+	char * const *t4 = new char*[10]; // t4 - 讼斡粤卧钨 土佑勺 账邻猎盘攀 瘟 char*
+	const char * const * t5;
+	t1 = argv;
+	// t2 = argv; // error: invalid conversion from 'char**' to 'const char**'
+	t2 = (const char**) argv;
+	t4 = argv;
+	t3[0] = argv[0];
+	// t4[0] = argv[0]; // error: assignment of read-only location '* t4'
+	t3[0] = new char[100];
+	//strcpy(t3[0],"text"); // error: invalid conversion from 'const char*' to 'char*'
+	strcpy(t4[0],"text"); // error: invalid conversion from 'const char*' to 'char*'
+	t3[0] = "test";
+	// t4[0] = "test"; // error: assignment of read-only location '* t4', warning: deprecated conversion from string constant to 'char*'
+	t5 = argv;
+	t5 = t3;
+	t5 = t4;
+}

tests/getline.cc

+#include <iostream>
+#include <string>
+#include <cstring>
+
+using namespace std;
+
+int main()
+{
+	string str;
+	getline(cin, str);
+	cout << "size of str=" << str.size() << ", strlen=" << strlen(str.c_str()) << endl;
+}

tests/int_unsigned.cc

+#include <stdio.h>
+
+int main()
+{
+	int a = 5;
+	int b = -5 ;
+	unsigned int c = 5;
+	unsigned int d = -5 ;
+	int *e = (int*)&d;
+	if (a < b)
+		printf("a<b\n");
+	if ( c < d)
+		printf("c<d\n");
+	printf("%x\n", *e);
+}