Stroustrup 5.9, exercise 10

[arnuld]

this does not work, i know there is some problem in the "for loop" of
"print_arr" function. i am not able to correct the weired results i am
getting. i have no compile time error, it is only semantic-bug that is
causing the trouble:

EXPECTED: january, february, march....december
GOT: january, january, january.........january

------------- PROGRAMME --------------
/* Stroustrup, 5.9, exercise 10

STSTAMENT:
define an array of strings,where strings contains the names months
.. Print those strings. Pass the array to a function that prints those
strings.


SOLUTION:

1.) 1st, i will print array int he "main" using "for" loop
and array indexing.

2.) then i wil print he array using a function and passing the array
to the function as argument(pass by reference).


NOTICE: posted code is implementation of (2)
*/

#include<iostream>

void print_arr(const char**, size_t);

int main()
{
const char* arr[] = {"january", "february", "march", "april", "may",
"june",
"july", "august", "september", "october", "november",
"december"};


const size_t arr_size = sizeof(arr) / sizeof(*arr);

print_arr(arr, arr_size);

return 0;
}


void print_arr(const char** arr, size_t arr_size)
{
const char** p = arr;

std::cout << "\n\tUSING FUNCTION\n";
for(unsigned int i=0; i < arr_size; ++i)
std::cout << *p << std::endl;
}

-------------- OUTPUT ----------------------
[arch@voodo tc++pl]$ g++ -ansi -pedantic -Wall -Wextra 5.9_ex-10-
function.cpp
[arch@voodo tc++pl]$ ./a.out

USING FUNCTION
january
january
january
january
january
january
january
january
january
january
january
january
[arch@voodo tc++pl]$

 

[Michael DOUBEZ]

arnuld a écrit :

this does not work, i know there is some problem in the "for loop" of
"print_arr" function. i am not able to correct the weired results i am
getting. i have no compile time error, it is only semantic-bug that is
causing the trouble:

EXPECTED: january, february, march....december
GOT: january, january, january.........january
[snip]

void print_arr(const char** arr, size_t arr_size)
{
const char** p = arr;

std::cout << "\n\tUSING FUNCTION\n";
for(unsigned int i=0; i < arr_size; ++i)
std::cout << *p << std::endl;
}

[snip]

Using pointer arithmetic, you forgot to increment p; use:
for(unsigned int i=0; i < arr_size; ++i,++p)

You can also use arr instead or just deference it:
for(unsigned int i=0; i < arr_size; ++i)
std::cout << arr << std::endl;


Michael