How to change string value with function in C?-CodePudding

void change(char *string){
    string = "Hello";
    printf("%s", string);
}

int main (void){
    char* s = "Hey";
    change(s);
    printf("%s", s);
    return 0;
}

Shouldn't the code above print "Hello", as the parameter passed to the function is a pointer?

CodePudding user response：

pass a char** if you want a reference to a pointer. Then you can change where the pointer in main points to.

CodePudding user response：

There are a few ways to do what you want. The most common are shown below. It might be worth investigating this to understand what's happening:

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


void
change(char const **string)
{
    *string = "Hello";
}

void
change2(char * string, size_t n)
{
    strncpy(string, "hello", n - 1);
}

int
main(void)
{
    char const *cs = "Hey";
    char * s;
    char buf1[32] = "ABC";
    char buf2[] = "XYZ";

    change(&cs);   
    change2(s = buf1, sizeof buf1);
    change2(s = buf2, sizeof buf2);

    return 0;
}