How can I replace a character in a string that is in a structure?

Question

Apologies if the question has already been answered before. I could not find any help.

My assignment is to create a function that takes a structure (which contains a string) in parameter and replace a character in that string. Right now I'm trying to replace spaces with the letter 'J' but I'm having some difficulty.

Heres my code:

func.h

typedef struct item item;
struct item {
    char * word;
};

void space(item * item, char letter);

func.c

void space(item * item, char letter) {

    char * mot = item->word;
    int size = strlen(item->word);
    printf("\n\n%s\n\n",mot);

    for(int i=0; i<=size; i++) {
        if(mot[i] == ' ') {
            mot[i] = letter;                
        }
    }

    printf("\n\nNEW WORD: ");
    printf("%s",mot);
    printf("\n\n");
}

main.c

int main(int argc, char *argv[]) {

    printf("\n---Program---\n\n");

    char *word;
    char add    = 'x';

    item * item = malloc(sizeof(item));

    item->word  = "this is a word";
    //printf("%s",item->word);

    printf("\n\n");

    space(item,add);

    return 0;
}

Here's the error I'm getting:

Seg fault!!!

Riley · Answer 1 · 2016-09-22T18:30:04.043

0

You're mallocing space for the struct, but not for the string inside the struct.

item * item = malloc(sizeof(item));
item->word  = malloc(sizeof(char) * MAXSTRINGSIZE); //add this line or something similar
strcpy(item->word, "this is a word");

edited Sep 22 '16 at 18:30

answered Sep 22 '16 at 18:24

Riley

698
6
11

All this does is leak the allocation. And sizeof(char) is 1. – Carl Norum Sep 22 '16 at 18:24
Or just `item->word = strdup("this is a word");` and save yourself a line. – Carl Norum Sep 22 '16 at 18:26
@CarlNorum Assuming you're on a POSIX system... – Oka Sep 22 '16 at 18:27
@CarlNorum It's more readable to include the type that you're allocating for. – Riley Sep 22 '16 at 18:29
That depends on who you ask, I guess. `sizeof(char)` is certainly not idiomatic. – Carl Norum Sep 22 '16 at 18:31
@CarlNorum Thanks ! Found the answer in the related question you mentioned. – John Livingston Sep 22 '16 at 18:37

How can I replace a character in a string that is in a structure?

1 Answers1