C++巢狀if語句

總是可以合法地巢狀if-else語句，這意味著可以在另一個if或else if語句中使用一個if或else if語句。

語法

巢狀if語句的語法如下所示：

if( boolean_expression 1) {
   // Executes when the boolean expression 1 is true
   if(boolean_expression 2) {
      // Executes when the boolean expression 2 is true
   }
}

您可以像巢狀if語句一樣，以類似的方式巢狀else if...else。

示例

#include <iostream>
using namespace std;
 
int main () {
   // local variable declaration:
   int a = 100;
   int b = 200;
 
   // check the boolean condition
   if( a == 100 ) {
      // if condition is true then check the following
      if( b == 200 ) {
         // if condition is true then print the following
         cout << "Value of a is 100 and b is 200" << endl;
      }
   }
   cout << "Exact value of a is : " << a << endl;
   cout << "Exact value of b is : " << b << endl;
 
   return 0;
}

當以上程式碼編譯並執行時，會產生以下結果：

Value of a is 100 and b is 200
Exact value of a is : 100
Exact value of b is : 200