How to use default in c language

The purpose of default: In the switch statement, the specified code block is executed when there is no matching case. Usage: 1. Syntax: switch (expression) { case constant 1: code block 1; break; ... default: code block n; break; } 2. The default code block is optional and is recommended to be included to handle unmatched Case. Example: When there is no matching case in the switch, the default code block will be executed, as in the following example that prints "D".

default usage in C language

#default keyword is used in the switch statement in C language. Used to specify the code block to be executed when there is no matching case in the switch.

Syntax

switch (expression) {
case constant 1:

<code>代码块1;
break;</code>

case constant 2:

<code>代码块2;
break;</code>

...
default:

<code>代码块 n;
break;</code>

}

Usage

default code block is optional but recommended to be included in the switch statement It handles all unmatched cases. Without a default block, nothing will be done if there is no matching case in the switch.

Example

The following example demonstrates the use of the default keyword:

#include <stdio.h>

int main() {
  int grade = 85;

  switch (grade) {
    case 90:
      printf("A");
      break;
    case 80:
      printf("B");
      break;
    case 70:
      printf("C");
      break;
    default:
      printf("D");
      break;
  }

  return 0;
}

In this example, when the value of the grade variable is 85, The switch statement has no matching case. Therefore, the default code block is executed, printing "D".

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