Differences

This shows you the differences between two versions of the page.

--- soft:c [2020/07/25 08:45] – Ce Zhang
+++ soft:c [2020/11/05 02:10] (current) – Ce Zhang
@@ Line 1: / Line 1: @@
 =====C++=====
-====Read & write files====
+==== 2D array ====
+<code>
+TGraph*** g = new TGraph**[Nfile];
+for(i loop) g[i] = new TGraph*[t[i]->Nentries];
+for(int j = 0; j<t[i]->Nentries;j++) g[i][j] = ...(TGraph *)...
+</code>
+====EOF====
+<code>
+<<EOF        //开始
+....
+EOF            //结束
+//将一个文件的内容输出到另一个文件中：
+# cat fileA > fileB
+//将"<< EOF EOF"替代输入对象文件fileA：
+# cat << EOF > fileB
+//命令执行后，提示用户输入内容，输入结束后，用户的输入内容被保存到了fileB中。
+</code>
+====I/O====
 <code>
@@ Line 32: / Line 53: @@
 </code>
-====将变量名替换为字符串====
+<code>
+std::vector<char> v;
+	if (FILE *fp = fopen("filename", "r"))
+	{
+		char buf[1024];
+		while (size_t len = fread(buf, 1, sizeof(buf), fp))
+			v.insert(v.end(), buf, buf + len);
+		fclose(fp);
+	}
+</code>
+====将变量名替换为字符串====
+<code>
 #define name2str(name) (#name)
+</code>
+<code>
+#define xstr(s) str(s)
+#define str(s) #s
+#define foo 4
+     str (foo)
+          ==> "foo"
+     xstr (foo)
+          ==> xstr (4)
+          ==> str (4)
+          ==> "4"
+ </code>
+====函数指针作为参数====
+<code>
+void DiffusionModel (bool (*GeometryFunction)(double, double, double)) )
+bool InsideAerogel(double x, double y, double z);
+DiffusionModel(
+    InsideAerogel
+);
+</code>
+====char * 转换 (for input arg.)====
+<code>
+//char* to int
+int a = stoi(argv[1]);
+//char* 转 float/double
+float b = stof(argv[2]);
+double bb = stod(argv[2]);
+//char* 转 string (可以直接转）
+string str = argv[3];
+cout << a << endl << b << endl << bb << endl << str << endl;
+</code>