C / C++，如果带有示例，则为梯形图

C / C++中的“决策制定”有助于编写决策驱动的语句并根据某些条件执行特定的代码集。

在C / C++中， if-else-if阶梯帮助用户从多个选项中进行选择。 C / C++ if语句从上至下执行。一旦控制if的条件之一为true，就会执行与if关联的语句，其余的C else-if阶梯将被绕过。如果所有条件都不成立，则将执行最终的else语句。

句法：

if (condition)
    statement 1;
else if (condition)
    statement 2;
.
.
else
    statement;

if-else-if阶梯的工作：

1. 控制属于if块。
2. 流程跳至条件1。
3. 条件已测试。
   1. 如果Condition得出的结果为true，请转到步骤4。
   2. 如果Condition得出false，请转到步骤5。
4. 当前块被执行。转到步骤7。
5. 流程跳至条件2。
   1. 如果Condition得出的结果为true，请转到步骤4。
   2. 如果Condition得出false，请转到步骤6。
6. 流程跳至条件3。
   1. 如果Condition得出的结果为true，请转到步骤4。
   2. 如果Condition得出false，则执行else块。转到步骤7。
7. 退出if-else-if阶梯。

流程图if-else-if梯形图：

范例1：

C

// C program to illustrate nested-if statement
  
#include 
  
int main()
{
    int i = 20;
  
    // Check if i is 10
    if (i == 10)
        printf("i is 10");
  
    // Since i is not 10
    // Check if i is 15
    else if (i == 15)
        printf("i is 15");
  
    // Since i is not 15
    // Check if i is 20
    else if (i == 20)
        printf("i is 20");
  
    // If none of the above conditions is true
    // Then execute the else statement
    else
        printf("i is not present");
  
    return 0;
}

C++

// C++ program to illustrate if-else-if ladder
#include 
using namespace std;
  
int main()
{
    int i = 20;
  
    // Check if i is 10
    if (i == 10)
        cout << "i is 10";
  
    // Since i is not 10
    // Check if i is 15
    else if (i == 15)
        cout << "i is 15";
  
    // Since i is not 15
    // Check if i is 20
    else if (i == 20)
        cout << "i is 20";
  
    // If none of the above conditions is true
    // Then execute the else statement
    else
        cout << "i is not present";
  
    return 0;
}

输出：

i is 20

空运行示例1：

1. Program starts.
2. i is initialized to 20.
3. condition 1 is checked. 20 == 10, yields false.
4. condition 2 is checked. 20 == 15, yields false.
5. condition 3 is checked. 20 == 20, yields true.
  5.a) "i is 20" gets printed.
6. "Outside if-else-if" gets printed.
7. Program ends.

范例2：

C

// C program to illustrate nested-if statement
  
#include 
  
int main()
{
    int i = 25;
  
    // Check if i is between 0 and 10
    if (i >= 0 && i <= 10)
        printf("i is between 0 and 10");
  
    // Since i is not between 0 and 10
    // Check if i is between 11 and 15
    else if (i >= 11 && i <= 15)
        printf("i is between 11 and 15");
  
    // Since i is not between 11 and 15
    // Check if i is between 16 and 20
    else if (i >= 16 && i <= 20)
        printf("i is between 16 and 20");
  
    // Since i is not between 0 and 20
    // It means i is greater than 20
    else
        printf("i is greater than 20");
}

C++

// C++ program to illustrate if-else-if ladder
  
#include 
using namespace std;
  
int main()
{
    int i = 25;
  
    // Check if i is between 0 and 10
    if (i >= 0 && i <= 10)
        cout << "i is between 0 and 10" << endl;
  
    // Since i is not between 0 and 10
    // Check if i is between 11 and 15
    else if (i >= 11 && i <= 15)
        cout << "i is between 11 and 15" << endl;
  
    // Since i is not between 11 and 15
    // Check if i is between 16 and 20
    else if (i >= 16 && i <= 20)
        cout << "i is between 16 and 20" << endl;
  
    // Since i is not between 0 and 20
    // It means i is greater than 20
    else
        cout << "i is greater than 20" << endl;
}

输出：

i is greater than 20

相关文章：

1. C / C++中的决策
2. C / C++ if else语句和示例
3. C / C++ if语句和示例
4. C / C++中的Switch语句
5. C / C++中的Break语句
6. 在C / C++中继续执行语句
7. C / C++中的goto语句
8. C / C++中的带有示例的return语句

想要从精选的最佳视频中学习和练习问题，请查看《基础知识到高级C的C基础课程》。