c - initialization makes integer from pointer

Question

I am trying get number ASCII for letter in char variable. My code so far is:

 int main (int argc,char* argv[]) {
    char c="A"; //here error
    char b="'"; //here error
    char d="z"; //and here error
    printf("%d\n %d\n %d\n",c,b,d); 
}

But I get the following errors:

analizer.c: In function ‘main’:
analizer.c:13:8: warning: initialization makes integer from pointer without a cast [enabled by default]
analizer.c:14:8: warning: initialization makes integer from pointer without a cast [enabled by default]
analizer.c:15:8: warning: initialization makes integer from pointer without a cast [enabled by default]

compiler is not rude, nothing personal, its telling you what the issues are. — t0mm13b
– t0mm13b, Commented May 19, 2016 at 16:28

MikeCAT · Accepted Answer · 2016-05-19 16:35:14Z

6

"A" is a string literal (an array of characters). 'A' is a character constant (an integer). What you want should be latter.

#include <stdio.h>

int main (int argc,char* argv[]) {
    char c='A';
    char b='\''; // use escape sequence
    char d='z';
    printf("%d\n %d\n %d\n",c,b,d); 
}

The compiler will allow you to extract elements of the arrays (string literals) like below, but using character constants should be better in this case.

#include <stdio.h>

int main (int argc,char* argv[]) {
    char c="A"[0]; // a typical way to deal with arrays
    char b=*"'"; // dereferencing of a pointer converted from an array
    char d=0["z"]; // a tricky way: this is equivalent to *((0) + ("z"))
    printf("%d\n %d\n %d\n",c,b,d); 
}

edited May 19, 2016 at 16:35

answered May 19, 2016 at 16:28

MikeCAT

75.1k11 gold badges50 silver badges71 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Linus · Accepted Answer · 2016-05-19 16:29:04Z

2

Basically you point to a string literal when you do this (which is invalid):

char c="A";

You need to write a single char to the variables:

char c='A';
char b='\'';
char b='z';

answered May 19, 2016 at 16:29

Linus

1,52818 silver badges35 bronze badges

Comments

Peter - Reinstate Monica · Accepted Answer · 2016-05-20 11:40:59Z

1

In C strings are just an array of characters which terminate with a \0. So if you want to use only one character, declare a char variable and use the character single quote. If you want to use a string, declare char array and use doublequote as

char a='A' //  just one character
char b[20]="Some_Text"// multiple characters(a string)

In the first case, a contains the integer value of 'A' but in the second, b contains the base address of the string it points to. Each character in array b[] must be accessed with indexes as b[0] b[1] etc.

You can use strings to represent single characters as

char a[]="A" // a string of size 1

and then you can print it's integer equivalent as

printf("%d",a[0]); //0th element of the string

or

use the single quote method as described in other answers.

edited May 20, 2016 at 11:40

Peter - Reinstate Monica

16.4k4 gold badges43 silver badges70 bronze badges

answered May 19, 2016 at 17:07

Anish Sharma

5253 silver badges17 bronze badges

2 Comments

Peter - Reinstate Monica Over a year ago

char a[1]="A" is unusual and misleading. It is equivalent, for example, to char a[1]="ABCDE"; the declared array of one element is initialized with the necessary number of subsequent characters from the character string literal, more specifically with the first character, the 'A'. The remaining characters in the literal are ignored. a will not be 0 terminated. It would be better to write char a[2]="A", and best to write char a[]="A".

Anish Sharma Over a year ago

@PeterA.Schneider You are absolutely correct. I just wanted to make things simpler for the OP. You are welcome to edit my answer if you find it misleading.

Collectives™ on Stack Overflow

c - initialization makes integer from pointer

3 Answers 3

Comments

Comments

or

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

or

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related