Easy tutorial for C / C ++ - string 4 (Two-dimensional arrays and pointer to string arrays)

Easy tutorial for C / C ++ - string 4 (Two-dimensional arrays and pointer to string arrays)

- Learn how to store multiple strings. You can define multiple one-dimensional arrays and save them as different array names. And you can also use a two-dimensional array to store multiple strings. Let's look at how to store strings using a two-dimensional array.

- In a two-dimensional array, rows can be represented by the number of strings to be stored, and columns by one greater than the length of the longest string (including the null character).

- Let's look at it in two ways: a two-dimensional array and a pointer to string array.

Example Code

#include <iostream>

#include <string.h>

using namespace std;

int main() {

     char st1[3][10] = { "black",

                                     "blue",

                                     "orange" };

     cout << " Print \'st1[3][10]\' " << endl ;

     for(int i=0; i<3; i++){

          cout << "st1[" << i << "] = " << st1[i] <<endl;

          }

     cout << endl ;

     char *st2[3] = { "white",

                                  "red",

                                  "pink" };

     cout << " Print \'*st2[3]\' " << endl ;

          for(int i=0; i<3; i++){

          cout << "st2[" << i << "] = " << st2[i] <<endl;

          }

     cout << endl ;

          for(int i=0; i<3; i++){

          cout << "*st2[" << i << "] = " << *st2[i] <<endl;

          }

     return 0;

}

- We have defined a two-dimensional array 'st1' to store strings. To store the three strings 'black, blue, orange', the rows and columns were set to 3 and 10, respectively. Let's print out the stored strings using the for loop. If you omit a column in a two-dimensional array and represent only the row elements, it represents the starting address of the row. We will print the start address (st1 [i]) of each line after the '<<' operator.

- Defined a pointer array '* st2 [3]' that stores three character pointers, and gave 'white, red, pink' as initial value. The pointer to array stores the start address value of each string.

- After the '<<' operator, we represent the elements of the pointer array (st2 [i]) and output the stored strings. Let's also print the '*' operator in front of the pointer array element.

results :

Print 'st1[3][10]'

st1[0] = black

st1[1] = blue

st1[2] = orange

 Print '*st2[3]'

st2[0] = white

st2[1] = red

st2[2] = pink

*st2[0] = w

*st2[1] = r

*st2[2] = p

- You can see three strings 'black, blue, orange' as a result of a two-dimensional array 'st1'.

- As a result of the pointer array 'st2', the string 'white, red, pink' is output.

- Each element of the pointer to array 'st2' stores the start address value of each string. You can see that the start (first) value of the string is printed because the '*' operator is prepended.