[C++] Call by Value/Call by Pointer/Call by Reference的範例

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1. Call by Value

1. int main()
   
2. {
   
3.   int a = 1;
   
4.   int b = a;
   
5.   return 0;
   
6. }

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2. Call by Pointer

1. void swap(int *address_a, int *address_b) {
   
2.   int temp = *address_a ;
   
3.   *address_a = *address_b;
   
4.   *address_b = temp;
   
5. }
   
6. 
   
7. int main() {
   
8.   int a = 1;
   
9.   int b = 0;
   
10.   swap(&a, &b); // 傳入a, b的address進行交換
    
11.   return 0;
    
12. }

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3. Call by Reference

1. void swap(int &address_a, int &address_b) {
   
2.   int temp = address_a ;
   
3.   address_a = address_b;
   
4.   address_b = temp;
   
5. }
   
6. 
   
7. int main() {
   
8.   int a = 1;
   
9.   int b = 0;
   
10.   swap(a, b); // 傳入a, b的address進行交換
    
11.   return 0;
    
12. }

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使用Call by Pointer跟Call by Reference傳遞參數給函式會實質變更變數數值！