Question

I’m trying to learn C now, I’m coming from Java and there is some stuff that is new to me.

I want to print a string and send an int and a string(char array) to another method. But I keep getting some errors that I don’t know how to fix.

Would really appreciate if someone could take their time and explain to me what’s wrong in my code. I’m quite disoriented at the moment with these pointers. When to use %s and %c when printing etc…

Code:

#include <stdio.h>

void main()
{
    int k = 10;
    char string;
    char *sptr;
    string = "hello!";  

    int *ptr;

    sptr = &string;

    ptr = &k; 
    printf("%s \n", &sptr);
    printf("Sending pointer.\n");

    sendptr(ptr, sptr);
}

And the errors.

test.c: In function ‘main’:
test.c:8:9: warning: assignment makes integer from pointer without a cast
test.c:15:2: warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘char **’
tezt.c: In function ‘sendptr’:
tezt.c:8:8: error: incompatible types when assigning to type ‘char[6]’ from type ‘char’

Thanks for your time! 🙂

First functions solved.

Second function i get this..

tezt.c: In function ‘sendptr’:
tezt.c:5:2: error: invalid initializer



#include <stdio.h>

void sendptr(int *test, char *fname)
{
    char fnamn[] = &fname;
    int pt;


    pt = *test;
    printf("%p \n", test);
    printf("%d \n", pt); 
    printf("%s \n", fnamn);
}

Answer 1

char string;
string = "hello!";  

First problem: you’re declaring string as a single char, not as an array. Also, you can only initialize the array to a string literal in a single statement.

char string[] = "hello!";

Second problem: sptr is a pointer-to-char, so it has to point to the first element of your string. Either of these will do:

char *sptr = string;
char *sptr = &string[0];

Then, when printing the string, just pass sptr directly.

printf("%s \n", sptr);

EDIT for your next question.

char fnamn[] = &fname;

You’re trying to assign a char** (pointer to pointer to char) to an array. That just won’t work. If you want to copy the string pointed to by fname into fnamn then you need to use a function such as strncpy.

char fnamn[MAX_STRING_SIZE];
strncpy(fnamn, fname, MAX_STRING_SIZE);

Having said that, if you just want to print the string, then print fname directly without copying it into your array first.