modify array element through pointer to a pointer

Question

I'm trying to build a program that modifies the element of an array through a pointer to a pointer. I loaded it into the debugger and I see that the value of my pointer changes, but for some reason that doesn't affect the element in the array. Is my pointer syntax wrong? Am I reassigning my pointer somewhere else?

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

#define SIZE 6

/*
 * 
 */


void change (char **x);

int main() {
    
    char arra[] = "Back";
    char *c = arra;
    
    change(&c);
    
    int i; 
    printf("%c", arra[0]);
    }
    
   

void change (char **x) {
    
    *x = "H";
    
}

Gopi · Accepted Answer · 2015-06-18 17:59:17Z

3

*x = "H";

should be

**x = 'H';

You are trying to modify the first character and character has to be within single quotes.

There is no need of pointer to pointer here. You can just pass the array which decays to a pointer when passed in the function parameterks as shown by @haccks

edited Jun 18, 2015 at 17:59

answered Jun 18, 2015 at 17:47

Gopi

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1 Comment

Eugeniu Rosca Over a year ago

Does and from your statement mean that's why?

haccks · Accepted Answer · 2015-06-18 17:47:09Z

2

No need to use pointer to pointer in this case. Just use pointer to char.

void change (char *x);

and call it as

change(c);

with the function body

 void change (char *x) { 
    *x = 'H';   
}

answered Jun 18, 2015 at 17:47

haccks

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