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I need to split up an input, into 5 different int variables. the format is like so: aabbcc-ddde. I need to take 2, 2, 2, 3 and 1 of the numbers, and assign them to int variables. But how do I do that?
Code:
int day, month, year, ctrlnr, gender;
char input[12];
cout << "Indtast venligst cprnr. i formatet ddmmċċ-cccc \n";
cin >> input;
day = ?
month = ?`
etc.
Here is a tip: You know how many characters each number will have. So start with splitting up that string to many small ones.
But how will that help me move them into int variables? I could just split them up into lesser strings, but they'd still be strings, not values.
Hmmm, can I maybe assign the whole string to an int variable after I split it up? I'll try.
true, you have a couple of options, either look up atoi or look up stringstream (search the board in both cases).
this input needs to be taken in as a char array?
No, I need it to devide the string into int values. 2 first numbers needs to be the day value, two next the month value and so on.
This is what I made, but it doesn't work, and I still can't figure out how to make the char arrays into int variables.Code:
int i=0, l=0;
char input[12], day[3], month[3], year[3], ctrlnr[4], gender[2];
cout << "Indtast venligst cprnr. i formatet xxxxxx-xxxx \n";
cin >> input;
while(i<2)
{
day[l] = input[i];
i++;
l++;
}
l=0;
while(i<4)
{
month[l] = input[i];
i++;
l++;
}
l=0;
while(i<6)
{
year[l] = input[i];
i++;
l++;
}
cout << day << month << year << "-";
you must have misunderstood... I was asking if you could instead just take in integers directly instead of dealing with a character array...
for example:
Code:...
int day,month,year;
cin>>day>>month>>year; //make yours more user-friendly by providing direction
cout<<day<<'/'<<month<<'/'<<year;
...
Ahh.
Can I just do that? I thought it needed a pish on the enter key to go to the next input.
Thanks, I'll try it out.
it does... you want everything on one line with just one press of the enter key?
in that case you were moving in the right direction the first time... you may want to invest some time in strncpy
Yea, I found out. :(
Any idea how to do it the other way?
you could try somethign like this:
IANAL (heh), and I have no clue if that will work... there's also probably a standard (or at least widely accpted) function to take the place of my 'clip' function, but I can't seem to remember one for now...Code:...
void clip(char*,int); //prototype for a function to come later
...
int main() //start the driver function after the includes and prototype
...
char*Data,cDay,cMonth,cYear; //declare char arrays for each
Data=new char[20]; //allocate memory
cDay=new char[5]; //allocate memory
cMonth=new char[5]; //more of the same
cYear=new char[5]; //one more time
int Day,Month,Year; //create integers (allocate memory ;) )
...
strncpy(data,cDay,2); //copy the first two characters into cDay
Day=atoi(cDay); //turn cDay into an integer and store in Day
clip(Data,2); //trim off those first two characters
...
}
void clip(char*Data,int index) //custom function
{
int Length=strlen(Data)-index; //the new length is going to be the current length minus what you take off
for(int i=0;i<index;i++) //go through the inner loop for as many chars as your taking off
{
for(int x=0;x<Length;x++) //go through the entire string
Data[x]=Data[x+1]; //move each character up one space
}
Data[Length]='\0'; //make sure there's a null-termination where you want it
}
your best bet is to probably look into the string class because that would make all this alot easier and get you away from the C-style strings you've been using...
Yea, maybe it's my best bet to try something with string instead. What you showed me there, was a little too advanced, even thou you tried your best to explain it :)
>>Data=new char[20]; //allocate memory
There is absolutely no reason to dynamically allocate memory in this situation, and you're also not delete[]'ing it at any point. Also, you don't need a clip() function at all:
Now it's all split up into different strings, assuming I have the parameters for strncpy correct. The trick is, you set 'iterator' to the start of the string, copy 2 characters from that position, move 'iterator' 2 characters to the right, copy 2 characters, move it 2 to the right, etc... You'll find that pointers are very nice for this kind of thing, and you really have no need for a C++ string here (and in fact it might be harder to do it with one). Then just use atoi() or a std::stringstream to convert the broken up strings into integers.Code:char data[20];
char a[3];
char b[3];
char c[3];
char d[4];
char e[2];
char* iterator = data;
strncpy(iterator, a, 2);
iterator += 2;
strncpy(iterator, b, 2);
iterator += 2;
strncpy(iterator, c, 2);
iterator += 3; //because there's a '-' between cc and ddd
strncpy(iterator, d, 3);
iterator += 3;
strncpy(iterator, e, 1);
Hope this helps!
**P.s.
major_small, I believe you're a step-2 pointer user :)
http://cboard.cprogramming.com/showt...eps#post393652
Thanks alot.
I don't really get pointers yet, so could you explain something?
Why do I need the pointer? Why can't I just declare it like this?Code:char* iterator = data;
Code:char iterator = data;
data was declared as an array of char, not as a single char. therefore, trying to assign data to a single char won't work. On the other hand, the name of an array acts like a pointer to the first element of the array, so the name of an array can be assigned to a pointer of the same type as the array.
Yes, char* and char array are very often interchangeable. In fact, if you take a look at major_small's code above, he uses char*'s wherever I use a char array instead (with very minor changes) ;)
>> you really have no need for a C++ string here (and in fact it might be harder to do it with one)
Decide for yourself: substr() http://www.cppreference.com/cppstrin...ls.html#substr
Yes, I know about substr() and c_str(), and they will work fine. But I personally like the C-style more than the C++ style in this case, if only because the C++ style requires an integer counter rather than directly pointing to the next block of memory... besides which, atoi() takes a c-style string (and yes I know about c_str() and stringstreams).Code:char* iterator = data;
strncpy(iterator, a, 2);
iterator += 2;
...
nA = atoi(a);
Code:int pos = 0;
a = data.substr(pos, 2);
pos += 2;
...
nA = atoi(a.c_str());
Ok, now I got how to divide them into different strings, but can anyone tell me how to convert them into intergers?
look up atoi and/or stringstream.
Someone already gave you the answer actually. Re-read the previous posts again, also in the cprogramming FAQ.
Yea, so I see. atoi is really simple, and does exactly what I want :D
Once again, thanks guys.
Sorry to ask for help so soon. I have tested the atoi translations, and they seem to work fine, yet all the whole program outputs is 000-00.
Code:
#include <vcl.h>
#include <iostream>
#include <stdlib>
#pragma hdrstop
using namespace std;
//---------------------------------------------------------------------------
#pragma argsused
int main()
{
int Iday, Imonth, Iyear, Ictrlnr, Igen, test;
char input[20], day[3], month[3], year[3], ctrlnr[4], gen[2];
char* i = input;
cout << "Indtast cprnr. i formatet xxxxxx-xxxx ";
cin >> input;
strncpy(i, day, 2);
i += 2;
strncpy(i, month, 2);
i += 2;
strncpy(i, year, 2);
i += 3;
strncpy(i, ctrlnr, 3);
i += 3;
strncpy(i, gen, 1);
Iday = atoi(day);
Imonth = atoi(month);
Iyear = atoi(year);
Ictrlnr = atoi(ctrlnr);
Igen = atoi(gen);
cout << Iday << Imonth << Iyear << "-" << Ictrlnr << Igen;
cin >> test;
return 0;
}
Actually it looks like the strncpy() lines are wrong. It should be
strncpy(month, i, 2);
etc.
And then it works :D
Thanks Hunter, you've been a great help.
No problem :)
I'm in trouble again.
I made the if statements, and tested them with cout's, but when I threw in the bool, it suddenly doesn't work. I have tried to look up bool, but I can't find anything that helps me out, and I can't see where it messes up. :(
It checks if the number is valid within the conditions given in the if files, and it worked. Then I added the bool variable, and the last part, and now the numbers don't work right. If I for ex. input 230378-4581, the integers return 232378-4581, when it should be 23378-3035.Code:bool valid = true;
int Iday, Imonth, Iyear, Ictrlnr, Igen, test;
char input[20], day[3], month[3], year[3], ctrlnr[4], gen[2];
char* i = input;
cout << "Indtast cprnr. i formatet xxxxxx-xxxx ";
cin >> input;
strncpy(day, i, 2);
i += 2;
strncpy(month, i, 2);
i += 2;
strncpy(year, i, 2);
i += 3;
strncpy(ctrlnr, i, 3);
i += 3;
strncpy(gen, i, 1);
Iday = atoi(day);
Imonth = atoi(month);
Iyear = atoi(year);
Ictrlnr = atoi(ctrlnr);
Igen = atoi(gen);
cout << Iday << Imonth << Iyear << "-" << Ictrlnr << Igen;
if(Imonth == 1 || Imonth == 3 || Imonth == 5 || Imonth == 7 || Imonth == 9 || Imonth == 11)
{
if(Iday > 31)
valid = false; //Here I used cout << " Invalid cprnr."
}
else if(Imonth == 4 || Imonth == 6 || Imonth == 8 || Imonth == 10 || Imonth == 12)
{
if(Iday > 30)
valid = false;
}
else if(Imonth == 2)
{
if(Iyear%4 == 0)
{
if(Iday > 29)
valid = false; //same
}
else if(!Iyear%4 == 0)
{
if(Iday > 28)
valid = false; //and so on
}
}
else if(Imonth > 12)
valid = false;
if(Iyear > 99)
valid = false;
if(Iday > 31)
valid = false;
if(valid == true) //added this for output.
cout << endl << input <<" is a valid cprnr. ";
else if(valid == false)
cout << endl << input << " is not a valid cprnr. ";
Not sure if this is the cause though, but still.Code:else if(!Iyear%4 == 0) // Problem here, take away the ! use != instead
{
if(Iday > 28)
valid = false; //and so on
}
Ok, nevermind. The bool just seems to mess everything up, so I used the int variable test instead, and it works as it's supposed to.