Limbajul C. "Insert a letter in string".

Fara prea multe comentarii (cu exceptia celor din cod :-), inca o problema din cursul de la University College Cork, menita sa fixeze notiuni precum siruri de caractere, tablouri, functii.

1.  Write and test a function that inserts a character anywhere in a string. The function should take the general form: strins(  char *string,  char character,  int position ).

Codul si printscreen-ul executiei:

#include <stdio.h>

/* The logical behind: once given the desired position in string for the new letter, every existent letter, starting from that index, should be right-shifted one position, so if the previous dimension of the string was n, the new dimension will be n + 1.
*/

           

int InsertLetter(char p[], int n, char c);

int main()

{

            char tab[81] = {"\0"}, c; // max 80 characters, not to mention '\0'

            int i = 0, j;

            puts("Gimmie a string to feed the array...\nEnd it with a tab if is less than 80 chars.");

            while(i < 80)

            {

                        tab[i] = getchar();

                        if(tab[i] == '\t')

                        {

                                    tab[i] = '\0';

                                    break;

                        }

                        else tab[i + 1] = '\0';

                        i++;

            }

            _flushall();

            puts("Now, gimmie a letter and an index. \nThe letter will be inserted in string to the specified position.\n");

            printf("The letter is: ");

            scanf("%c", &c);

            _flushall();

            printf("The index is: ");

            scanf("%d", &j);

            if(InsertLetter(tab, j, c)) printf("The modified string is:\n%s.\n", tab);

            return 0;

}

int InsertLetter(char p[], int n, char c)

{

            int l = 0, i;

            // we check the string dimension

            while(p[l++]);

            l--;; // we don't count the '\0'

            printf("Initial string dimension: %d.\n", l);

            if(l >= 80) // cannot insert at the very end

            {

                        printf("\nI can't make room for the %c letter.", c);

                        return 0;

            }

            else if(n > l)

            {

                        printf("\nI can't insert the %c letter at index %d.", c, n);

                        return 0;

            }

            else

            {

                        for(i = l - 1; i >= n; i--) p[i + 1] = p[i];

                        p[n] = c;

                        p[l + 1] = '\0';

            }          

            return 1;

}