q******0
发帖数: 15 | 1 See the code below. I am confused that "len = 5" from main function, "len =
4" from RemoveDuplicate function. When does terminate '\0' count? Thanks.
#include
using namespace std;
void RemoveDuplicate(char str[])
{
int len = sizeof(str)/sizeof(str[0]);
cout << "len = " << len << endl;
}
int main()
{
char a[] = "abcd";
int len = sizeof(a)/sizeof(a[0]);
cout << "len = " << len << endl;
RemoveDuplicate(a);
return 0;
} |
l*****a
发帖数: 14598 | 2 please use "abcde" as your input and check the result
=
【在 q******0 的大作中提到】
: See the code below. I am confused that "len = 5" from main function, "len =
: 4" from RemoveDuplicate function. When does terminate '\0' count? Thanks.
: #include
: using namespace std;
: void RemoveDuplicate(char str[])
: {
: int len = sizeof(str)/sizeof(str[0]);
: cout << "len = " << len << endl;
: }
: int main()
|
i**********e
发帖数: 1145 | 3 Try this and figure out why:
void foo(int str[])
{
int len = sizeof(str)/sizeof(str[0]);
cout << "len = " << len << endl;
}
int main()
{
int a[] = {1,2,3,4};
int len = sizeof(a)/sizeof(a[0]);
cout << "len = " << len << endl;
foo(a);
return 0;
} |
r*****k
发帖数: 1281 | 4 void RemoveDuplicate(char str[])
{
int len = sizeof(str)/sizeof(str[0]);
cout << "len = " << len << endl;
}
这上面这段code中，sizeof(str)是计算“the size of the pointer represented by
the array identifier”, which is always 4. |
S**I
发帖数: 15689 | 5 not necessarily always 4; size of a pointer is implementation defined.
by
【在 r*****k 的大作中提到】
: void RemoveDuplicate(char str[])
: {
: int len = sizeof(str)/sizeof(str[0]);
: cout << "len = " << len << endl;
: }
: 这上面这段code中，sizeof(str)是计算“the size of the pointer represented by
: the array identifier”, which is always 4.
|
r*****k
发帖数: 1281 | 6 Yes, you are right. I meant that in lz's test case, it's always 4.
【在 S**I 的大作中提到】
: not necessarily always 4; size of a pointer is implementation defined.
:
: by
|
a*****a
发帖数: 495 | 7 ...not
【在 r*****k 的大作中提到】
: Yes, you are right. I meant that in lz's test case, it's always 4.
|
p*i
发帖数: 411 | 8 If you are on a 64bit environment and compiles the source code in 64bit mode
, the main function will output len = 5 (length of the C string) and the
RemoveDuplicate function will output len=8, which is exactly sizeof(char*)/
sizeof(char)
=
【在 q******0 的大作中提到】
: See the code below. I am confused that "len = 5" from main function, "len =
: 4" from RemoveDuplicate function. When does terminate '\0' count? Thanks.
: #include
: using namespace std;
: void RemoveDuplicate(char str[])
: {
: int len = sizeof(str)/sizeof(str[0]);
: cout << "len = " << len << endl;
: }
: int main()
|
