函數指標的定義與操作樣本

//任意輸入兩個運算元和一個加、減運算子，完成對應的加減運算，並給出結果<br />//樣本：輸入3+5，輸出3+5=8<br />#include <iostream><br />using namespace std;<br />float add(float x, float y) {<br />cout << x << "+" << y << "=";<br />return x + y;<br />}<br />float sub(float x, float y) {<br />cout << x << "-" << y << "=";<br />return x - y;<br />}<br />int main() {<br />float a, b;<br />char c;<br />float (*p) (float, float);//此處說明了一個函數指標，能指向具有兩個float形參並返回float的函數。<br />while (1) {<br />cout << "a op b" << endl;<br />cin >> a >> c >> b;<br />switch (c) {<br />case '+': p = add; break;<br />case '-': p = sub; break;<br />default: cout << "input error!" << endl;return 1;<br />}<br />cout << p(a, b) << endl;<br />cout << "continue ? (y/n):";<br />cin >> c;<br />if (c != 'y' && c != 'Y') break;<br />}<br />return 0;<br />}