Shulou(Shulou.com)06/01 Report--

There is a problem about the return value in the function in C language. the local variables in the function are mainly opened up on the stack, and the function variables are recycled. In view of the worthiness of function return, the following specific examples are given to illustrate:

The return value of a function is a local variable defined in the function

This type of return value can be used in the main function, because when returning a local variable is worth it, it is worth a copy, and that's all we need in the main function, so it's OK, for example.

Int fun (char * arr)

{

Int num = 0

While (* arr! ='\ 0')

{

Num = num * 10 + * arr -'0'

Arr++

}

Return num

Printf ("d", num)

}

Int main ()

{

Int tem = 0

Char * arr = "12345"

Tem = fun (arr)

Printf ("d", tem)

System ("pause")

Return 0

}

two。 The function returns the pointer variable defined in the function

Char * fun ()

{

Char * arr = "1234"

Return arr

}

Int main ()

{

Char * tem = fun ()

Printf ("% s", tem)

System ("pause")

Return 0

}

This is also correct in the process of running.

3. Function cannot return the address of a local variable

Int * fun ()

{

Int a = 10

Return & a

}

Int main ()

{

Int * tem = fun ()

Printf ("% d", * tem)

System ("pause")

Return 0

}

4. Function cannot return the first address of the array

Int * fun ()

{

Int arr [] = {1,2,3,4}

Return arr

}

Int main ()

{

Int * tem = fun ()

System ("pause")

Return 0

}

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.