C | Clases de almacenamiento y calificadores de tipo | Pregunta 9

¿Producción?

#include <stdio.h>
int fun()
{
  static int num = 16;
  return num--;
}
  
int main()
{
  for(fun(); fun(); fun())
    printf("%d ", fun());
  return 0;
}

(A) Bucle infinito
(B) 13 10 7 4 1
(C) 14 11 8 5 2
(D) 15 12 8 5 2

Respuesta: (C)
Explicación: Dado que num es estático en fun() , el antiguo valor de num se conserva para llamadas a funciones posteriores. Además, dado que la declaración return num – es postfijo, devuelve el valor anterior de num y actualiza el valor para la próxima llamada a la función.

fun() called first time: num = 16 // for loop initialization done;


In test condition, compiler checks for non zero value

fun() called again : num = 15

printf("%d \n", fun());:num=14 ->printed

Increment/decrement condition check

fun(); called again : num = 13

----------------

fun() called second time: num: 13 

In test condition,compiler checks for non zero value

fun() called again : num = 12

printf("%d \n", fun());:num=11 ->printed

fun(); called again : num = 10

--------

fun() called second time : num = 10 

In test condition,compiler checks for non zero value

fun() called again : num = 9

printf("%d \n", fun());:num=8 ->printed

fun(); called again   : num = 7

--------------------------------

fun() called second time: num = 7

In test condition,compiler checks for non zero value

fun() called again : num = 6

printf("%d \n", fun());:num=5 ->printed

fun(); called again   : num = 4

-----------

fun() called second time: num: 4 

In test condition,compiler checks for non zero value

fun() called again : num = 3

printf("%d \n", fun());:num=2 ->printed

fun(); called again   : num = 1

----------

fun() called second time: num: 1 

In test condition,compiler checks for non zero value

fun() called again : num = 0 => STOP 

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