Initial commit

c++/Others/A shared resource example..cpp

@@ -0,0 +1,56 @@
+A shared resource example.
+#include <iostream>
+#include <cstring>
+using namespace std;
+
+class output {
+  static char sharedResource[255]; // this is the shared resource
+  static int inuse;        // buffer available if 0; in use otherwise
+  static int oindex;       // index of sharedResource
+  char str[80];
+  int i;                   // index of next char in str
+  int who;                 // identifies the object, must be > 0
+public:
+  output(int w, char *s) { 
+     strcpy(str, s); 
+     i = 0; 
+     who = w; 
+  }
+
+  int putbuf() 
+  {
+    if(!str[ i ]) {         // done outputting
+      inuse = 0;            // release buffer
+      return 0;             // signal termination
+    }
+    if(!inuse)              // get buffer
+        inuse = who; 
+    if(inuse != who)        // in use by someone else
+        return -1; 
+    if(str[ i ]) {          // still chars to output
+      sharedResource[oindex] = str[ i ];
+      i++; oindex++;
+      sharedResource[oindex] = '\0';// always keep null-terminated
+      return 1;
+    }
+    return 0;
+  }
+  void show() { 
+     cout << sharedResource << '\n'; 
+  }
+};
+
+char output::sharedResource[255];   // this is the shared resource
+int output::inuse = 0;      // buffer available if 0; in use otherwise
+int output::oindex = 0;     // index of sharedResource
+
+int main()
+{
+  output object1(1, "This is a test"), object2(2, " of statics");
+
+  while(object1.putbuf() | object2.putbuf()) ; // output chars
+
+  object1.show();
+
+  return 0;
+}