It depends on what you mean by "empty". If you just want a zero-length string, then your example will work.
This will also work:
buffer[0] = '\0';
If you want to zero the entire contents of the string, you can do it this way:
memset(buffer,0,strlen(buffer));
but this will only work for zeroing up to the first NULL character.
If the string is a static array, you can use:
memset(buffer,0,sizeof(buffer));
It depends on what you mean by "empty". If you just want a zero-length string, then your example will work.
This will also work:
buffer[0] = '\0';
If you want to zero the entire contents of the string, you can do it this way:
memset(buffer,0,strlen(buffer));
but this will only work for zeroing up to the first NULL character.
If the string is a static array, you can use:
memset(buffer,0,sizeof(buffer));
Two other ways are strcpy(str, ""); and string[0] = 0
To really delete the Variable contents (in case you have dirty code which is not working properly with the snippets above :P ) use a loop like in the example below.
#include <string.h>
...
int i=0;
for(i=0;i<strlen(string);i++)
{
string[i] = 0;
}
In case you want to clear a dynamic allocated array of chars from the beginning, you may either use a combination of malloc() and memset() or - and this is way faster - calloc() which does the same thing as malloc but initializing the whole array with Null.
At last i want you to have your runtime in mind. All the way more, if you're handling huge arrays (6 digits and above) you should try to set the first value to Null instead of running memset() through the whole String.
It may look dirtier at first, but is way faster. You just need to pay more attention on your code ;)
I hope this was useful for anybody ;)
How to check if C string is empty - Stack Overflow
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Since C-style strings are always terminated with the null character (\0), you can check whether the string is empty by writing
do {
...
} while (url[0] != '\0');
Alternatively, you could use the strcmp function, which is overkill but might be easier to read:
do {
...
} while (strcmp(url, ""));
Note that strcmp returns a nonzero value if the strings are different and 0 if they're the same, so this loop continues to loop until the string is empty.
Hope this helps!
If you want to check if a string is empty:
if (str[0] == '\0')
{
// your code here
}
Brand new to C, and I am told that there is no string data type. So I am just curious, if that id the case, then how exactly is something like: printf(“Hello World”) a thing?
For some reason, the name variable becomes empty even though I gave it an input.
Code:
#include <stdio.h>
int main(){
char name[16];
short unsigned int age;
printf("What is your name? ");
scanf("%s", &name);
printf("How old are you? ");
scanf("%u", &age);
printf("Hello, %s.\n", name);
printf("You are %u years old\n", age);
return 0;
}Terminal:
What is your name? Momus How old are you? 99 Hello, . You are 99 years old
I seems that the value for name was changed in the part somewhere in the part that prints "How old are you? " and the scanf() for the value of age because it works when I do this.
Code:
#include <stdio.h>
int main(){
char name[25];
short unsigned int age;
printf("What is your name? ");
scanf("%s", &name);
printf("Hello, %s.\n", name);
printf("How old are you? ");
scanf("%u", &age);
printf("You are %u years old\n", age);
return 0;
}Terminal:
What is your name? Momus Hello, Momus. How old are you? 99 You are 99 years old
Does anyone know what happened? How do I make it so that the first one will show the input? Thanks!
How do I initialize it to anything other than zero or NULL? I just want an empty string array, which I can use to store text with the help of a for loop. I dont want to assign it the function of GetString. If I declare the array in between an operation like.
string c_txt[i] = (p_txt[i] + key) % 26;
where c_txt is the array containing enciphered text, p_txt is array containing plain text, the console pops me an error saying "variable-sized object may not be initialized".
Also, string c_txt = NULL; desent work for obvious reasons. So how do I declare this string array?
P.S : I have a really bad feeling that this is a really dumb question and I`m making a fool of myself in front of the staff. What am I missing?
When I try using .isEmpty() or isspace() it gives me the message that "expression must have class type" and str != "" doesn't seem to work. The type I'm using is "const char *".
In addition to Will Dean's version, the following are common for whole buffer initialization:
Copychar s[10] = {'\0'};
or
Copychar s[10];
memset(s, '\0', sizeof(s));
or
Copychar s[10];
strncpy(s, "", sizeof(s));
You want to set the first character of the string to zero, like this:
Copychar myString[10];
myString[0] = '\0';
(Or myString[0] = 0;)
Or, actually, on initialisation, you can do:
Copychar myString[10] = "";
But that's not a general way to set a string to zero length once it's been defined.