Diff: FunctionPointer.hpp

Revision:

0:bb939e0bc6e2

Child:

1:bbb9f0c3e523

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FunctionPointer.hpp	Sun Oct 15 11:41:48 2017 +0000
@@ -0,0 +1,50 @@
+// 関数ポインタの使用例
+#include <cmath>
+
+void (*fp1)(int);
+void (*fp2)(int&);
+
+// typedef を使って一種の型名として扱う例
+typedef float (*FP3)(float);
+FP3 fp3Sin = sinf;
+FP3 fp3Cos = cosf;
+
+void printA(int x) { printf("printA: x = %d\r\n", x); }
+void printB(int x) { printf("printB: x = %d\r\n", 2*x); }
+
+void getA(int& a) { a = 2; }
+void getB(int& a) { a = 5; }
+
+// 関数ポインタの配列
+void (*fp4[])(int) =  { printA, printB };
+// 関数ポインタの配列（typedef を使う場合）
+typedef void (*FP5)(int);
+FP5 myFp[] = { printA, printB };
+
+void SwPointer(int k)
+{
+    printf("k = %d\r\n", k);
+
+    if (k==0) fp1 = printA;
+    else      fp1 = printB;
+    fp1(100);
+    
+    if (k==0) fp2 = getA;
+    else      fp2 = getB;
+    int x;
+    fp2(x);
+    printf("nx = %d\r\n", x);
+
+    fp4[k](100);
+    myFp[k](10);
+}
+
+void MyFunctionPointer()
+{
+    SwPointer(0);
+    SwPointer(1);
+
+    printf("\r\n");
+    printf("sin: %f\r\n", fp3Sin(3.1415926536f/3.0f));
+    printf("cos: %f\r\n", fp3Cos(3.1415926536f/3.0f));
+}