Printing String from array

Question

I know how to program Java and now I'm trying to learn C programming.

I want to write out a String from an Array of chars that I have created, and write out every String in one line (I'm creating a console application).

So far I have got this;

int main()
{
    int i;
    int j;
    char aarhus[] = {'\x8F','r','h','u','s',' ','H','\0'};
    char esbjerg[] = {'E','s','b','j','e','r','g','\0'};
    char stationer[] = {*aarhus,*esbjerg};
        for (j=0;stationer[j] != '\0';j++) {
            printf("%c\n", stationer[j]);
        }
    return 0;
}

with the includes in the top of course. But when I launch the program, it only writes ÅEEsbjerg and not Århus Esbjerg (both on a single line for itself, as I want it to). If I add \0 in the stationer[], all I get is ÅE on the same line. I have been trying to fix this for hours but nothing so far. I hope you can help. Thanks in advance

Marius Bancila · Accepted Answer · 2014-02-27 12:48:33Z

1

You're probably looking for something like this:

int main()
{
   int j;
   char aarhus[] = {'\x8F', 'r', 'h', 'u', 's', ' ', 'H', '\0'};
   char esbjerg[] = {'E', 's', 'b', 'j', 'e', 'r', 'g', '\0'};
   char* stationer[] = {aarhus, esbjerg, 0};
   for(j = 0; stationer[j] != 0; j++) 
   {
      printf("%s", stationer[j]);
   }
}

or maybe this:

int main()
{
   int j;
   char aarhus[] = {'\x8F', 'r', 'h', 'u', 's', ' ', 'H', '\0'};
   char esbjerg[] = {'E', 's', 'b', 'j', 'e', 'r', 'g', '\0'};
   char* stationer[] = {aarhus, esbjerg};
   int count = sizeof(stationer) / sizeof(char*);
   for(j = 0; j < count; j++) 
   {
      printf("%s", stationer[j]);
   }
}

edited Feb 27, 2014 at 12:48

answered Feb 27, 2014 at 12:39

Marius Bancila

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4 Comments

Zuenonentu Over a year ago

Thanks, I used your first solution. I got errors though about I couldn't declare j in the for loop and nullptr was unknown, so I declared j in the top of the function, and added '\0' as the last element in stationer[]

Marius Bancila Over a year ago

Oops, sorry, that was C not C++. I hope my edited code is better.

Diti Over a year ago

@Marius I wouldn't recommend to a C begineer to compute the size of an array using sizeof (as they would wonder why it doesn't work in a function, because of the promotion to pointer).

Michael F Over a year ago

@Diti: on the other hand, maybe it's about time they learned why. :)

Rahul · Accepted Answer · 2014-02-27 12:41:58Z

1

Change

 char *stationer[] = {aarhus,esbjerg};

and use

 printf("%s", stationer[j]);

answered Feb 27, 2014 at 12:41

Rahul

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Comments

Michael F · Accepted Answer · 2014-02-27 13:20:39Z

Your code has many problems.

Arrays in C are not terminated. Your loop for (j=0;stationer[j] != '\0';j++) { seems to assume stationer contains the character '\0', yet your definition did not contain it.

Second, your program currently only prints two characters which are contained in stationer. The fact you see more characters of the esbjerg array is an example of undefined behaviour - you have run past the end of the array, therefore you are reading (and printing) garbage.

Furthermore, you have not included a newline '\n' character in your printf format. printf will not do that automatically for you like println does.

So, to sum up:

int main()
{
    char aarhus[] = {'\x8F','r','h','u','s',' ','H','\0'};
    char esbjerg[] = {'E','s','b','j','e','r','g','\0'};

    /* An array of pointers to char. */
    char *stationer[] = {aarhus, esbjerg, NULL};

    int index = 0;
    /* Print each array of character as a string "%s": */
    for (index = 0 ; stationer[index] != NULL; ++index) {
            printf("%s", stationer[index]);
    }
    return 0;
}

Last but not least, printf will handle 'Å' correctly if your locale supports it.

n0p · Accepted Answer · 2014-02-27 12:42:01Z

0

This should work:

printf("%s", aarhus);
printf("%s", esbjerg);

Because you don't add a \n they should be printed on the same line.

About your early termination I think it is the initialization of stationer that is in cause. You should try something like this (you want to double-check the sizes considering \0, \n etc):

// Allocate a new string 
unsigned char * stationer = malloc(sizeof(aarhus)+sizeof(esbjerg) -1); // -1 for the extra \0
// Copy your 1st string
memcpy(stationer, aarhus, sizeof(aarhus));
// Append the second
memcpy(stationer + sizeof(aarhus), esbjerg, sizeof(esbjerg));
// print it
printf("%s", stationer);

edited Feb 27, 2014 at 12:42

answered Feb 27, 2014 at 12:33

n0p

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1 Comment

n0p Over a year ago

Even better: strncat !

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