How do I put a int32_t into a char array? (c++)

Question

How do I put:

int32_t x = someValue;

Into my char array:

char * msg = new char[65546]();

Any help would be appreciated!

Do you want to get a string version of the number in the integer? Then you might want to check out [`std::to_string`](http://en.cppreference.com/w/cpp/string/basic_string/to_string). And if you want to use strings, use `std::string` instead of character arrays. — Some programmer dude, Sep 18 '13 at 16:47
You want to convert the int32_t value x to array of characters? — ArmenB, Sep 18 '13 at 16:47
@Martin I want the string representation of the number so that I could print it to console. — CodeDoctorJL, Sep 18 '13 at 16:48

score 3 · Accepted Answer · answered Sep 18 '13 at 16:51

That entirely depends on the way you want to store the value in the array. If you want to store byte-by-byte you can use the following code:

 int32_t x=someValue;
 char *ptr = (char*)&x;
 char *msg = new char[5];
 for(int i=0;i<4;++i, ++ptr)
    msg[i] = *ptr;

Care should be taken while using the above method. Because some systems use big-endian while the others may use little-endian.

On the other hand, if you want to store digit-by-digit into the char array, use the following:

 int32_t x=someValue;
 int digs[12], count=0;
 char *msg = new char[12];
 while(x>0)
 {
     digs[count++]=x%10;
     x/=10;
 }
 int i=0;
 while(count--)
 {
     msg[i++] = digs[count] +'0';
 }

Either way works. But its better to prefer the second one. Since it is easy to convert back to integer.

the second method is exactly what I was looking for, thanks nitish712! — CodeDoctorJL, Sep 18 '13 at 17:09

score 2 · Answer 2 · answered Sep 18 '13 at 16:51

2

If you want to print the value, why not just do it?

std::cout << "x = " << x << '\n';

answered Sep 18 '13 at 16:51

Some programmer dude

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I think it should be `"\n"` rather than `'\n'` ?? – nitish712 Sep 18 '13 at 16:54
In my application it doesn't show the std::cout for some reason. But I can print char arrays onto the screen. – CodeDoctorJL Sep 18 '13 at 16:57
Sorry. My bad. Ignore it. I forgot that single quotes can be used for single characters... – nitish712 Sep 18 '13 at 16:57
@CodeDoctorJL That's probably the question you should be asking. Don't just do random things until you find something that seems to work. Find out why you `std::cout` isn't working for you. – bames53 Sep 18 '13 at 17:08
@barnes53, Yes you're right. I will be searching into that later. – CodeDoctorJL Sep 18 '13 at 17:13

score 1 · Answer 3 · answered Sep 18 '13 at 16:48

1

    char* msg = new char[123];
int32_t x = 123;
int offset = 0;
memcpy(msg + offset, reinterpret_cast<char*>(&x), sizeof(int32_t));

answered Sep 18 '13 at 16:48

TVOHM

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Sorry, I just noticed your further comment to your question. If you want to print the value as a string you can easily do this as Joachim suggested, otherwise you could use std::to_string(x) or the itoa function. – TVOHM Sep 18 '13 at 16:56

How do I put a int32_t into a char array? (c++)

3 Answers3