CODEWITHSUNDEEP
carrayschar
mazix
mazix

Reputation: 2604

Change letter in array for 3 different letter

I need to change the text in array in a way, that everywhere I have a character, I need to change it to123.

Example: for the given text: ayasxka I should got this: 12123k123 or this 12323k123 text.

I almost got it to work, but instead of k between numbers, I got s, I mean, this is my result: 12123s123.

int main()
{
    int i, j = 0;
    char t[] = "ayasxka";
    char *r = malloc(sizeof(char) * (strlen(t) + 2));
    memset(r, '\0', (strlen(t) + 1));

    for(i=0; t[i] != '\0'; i++)
    {
        if(t[i] == 'a')
        {
            r[i] = '1';
            r[i+1] = '2';
            r[i+2] = '3';
        }
        else
            r[i+2] = t[i];
    }

    printf("%s\n", r);
    free(r);

    return 0;
}

Upvotes: 0

Views: 44

Answers (3)

BLUEPIXY
BLUEPIXY

Reputation: 40145

int i;// j = 0;//unused `j`
char t[] = "ayasxka";
char *r = calloc(strlen(t) + 2 + 1, sizeof(char));//change size, +2: for last a, +1: for NUL
//memset(r, '\0', (strlen(t) + 1));//calloc initialize by 0

for(i=0; t[i] != '\0'; i++){
    if(t[i] == 'a'){
        r[i]   = '1';
        r[i+1] = '2';
        r[i+2] = '3';
    }
    else if(r[i] == '\0'){//Not yet been set to the value
        r[i] = t[i];
    }
}

printf("%s\n", r);//12123k123
free(r);

char t[] = "ayasxka";
int i, len = strlen(t);
char *r = calloc(len + 2 + 1, sizeof(char));

for(i=len-1; i>=0; --i){
    if(t[i] == 'a'){
        r[i]   = '1';
        r[i+1] = '2';
        r[i+2] = '3';
    }
    else if(r[i] == '\0'){
        r[i] = t[i];
    }
}

printf("%s\n", r);//12323k123
free(r);

Upvotes: 0

Peeder
Peeder

Reputation: 79

In your algorithm you should use:

for(i=0; t[i] != '\0'; i++)
{
    if(t[i] == 'a')
    {
        j = i;
        r[j++] = '1';
        r[j++] = '2';
        r[j++] = '3';
    }
    else if(j==i)
        r[j++] = t[i];
}
r[j] = '\0';

and in your malloc you should add +1 character for the '\0', because strlen() doesn't count that, so

char *r = malloc(3 + strlen(t));

instead of

char *r = malloc(2 + strlen(t));

This will give you 12123k123

Upvotes: 2

Iharob Al Asimi
Iharob Al Asimi

Reputation: 53016

The problem is strlen(t) + 2 is not enough, consider the worst case i.e. the string is just made of only a characters, then it should be 

char *r = malloc(3 * strlen(t) + 1);

and szieof(char) == 1 is madatory by the way.

And you will need a counter for the position in the r string, say j

Try this

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

int main()
{
    int i, j = 0;
    char t[] = "ayasxka";
    /* don't call strlen multiple times, store the value if it wont change */
    size_t length = strlen(t);

    /* it doesn't matter how unlikely malloc will fail, check that + */
    char *r = malloc(3 * length + 1); /*                           | */
    if (r == NULL) /* <--------------------------------------------+ */
        return -1;
    for (i = 0 ; t[i] != '\0' ; i++)
    {
        if(t[i] == 'a')
        {
            r[j++] = '1';
            r[j++] = '2';
            r[j++] = '3';
        }
        else
            r[j++] = t[i];
    }
    /* you don't need the memset */
    r[j] = '\0';

    printf("%s\n", r);
    free(r);

    return 0;
}

Upvotes: 2

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