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How can I put an integer value in a string? something like:
I tried testing this out as part of a program, and after messing about a bit couldn't get it to work. Even though it compiled, when it ran, no string was printed.Code:int a=5;
char string[]=a;
printf("\n%s\n",string);
Also, if there is a way, can it be done for integers greater than 1 digit long also?
try this:Quote:
Originally Posted by bertazoid
Code:#include <stdio.h>
int main(void)
{
int a = 5;
char string[32] = "This is my string.";
sprintf(string, "%s %d", string, a);
printf("%s", string);
return 0;
}
You can give an element of a string an integer value.Code:#include <stdio.h>
int main () {
int a=97;
char string=a;
printf("%c\n",string);
}
> sprintf(string, "%s %d", string, a);
Right idea, but the result should go into a separate string.
Very few functions are guaranteed to do the right thing when you're modifying the thing you're reading from.
Thanks for the replies, I tried:
And it returned "24 24 3". Why does it print 'a,a,b', rather than 'a,string,b'?Code:int main (void) {
int a=24;
int b=3;
char string[32]="x^ ";
sprintf(string,"%d%s%d",a,string,b);
printf("%s\n",string);
return 0;
}
just noticed the new string part. I will try that out.
As Salem points out in post #4: You probably do not want to READ from and WRITE to the same string - you never know what sprintf() does to the input string - it almost certainly doesn't copy it before starting to write to the output string.
--
Mats
Yeh thanks, I missed that when I made my post, and I tried it and it worked. hoorah!Quote:
Originally Posted by matsp
I have a new question, I'm using sprintf sucessfully now, and for what I want to do, the first thing I'm writing to the string is a char e.g:
The problem is, this char is declared in a nested if statement, and only in one of the three cases do I want to actually have anything in there. for the other three cases, I want this to be ignored. I tried declaring the char only on this one case, and when the other two cases happened I got a hexagon with a question mark printed, indicating that I'm trying to print a char that hasn't been declared (It did compile).Code:sprintf(string,"%c blahblah",char1);
I also tried using
but the first didn't compile, and the problem with the second is tha I don't want a space...just nothing at all. Is there something else I can use, between the single quotes?..I'd really like to do this without having to add more if/select statements (if possible).Code:char char1=''; //nothing entered
and
char char1=' '; //with space
edit: Hmmm, can I use the null character, '\0'?
That seems like very dubious code. if you always want "x^ " printed within the string why not just put "%dx^ %d" instead of trying to pass a string into itself... which will really not do what you are wanting at all.Quote:
Originally Posted by bertazoid
Yeh, I changed that already, after realising the same thing. :)Quote:
Originally Posted by master5001
Snap! Its more satisfying to notice that on your own, I am willing to bet :) Keep up the good coding, friend.
There are a few ways to solve this problem. Simplest is to set it to '\0' and then check if it's '\0' - in that case, don't print it [putting a '\0' there will make string zero-length, becasuse sprintf isn't clever enough to know that you don't want a '\0' at the beginning of the string and thus make it an empty string].Quote:
Originally Posted by bertazoid
The second option is to use a char array instead of a single char. An empty string "" will print as "nothing" in sprintf.
The third option is to use different format strings - only put the %c in the format string if it's actually needed - otherwise it will be ignored. Just beware that this ONLY works when it's the last argument(s) of sprintf that you want to skip, there is no way to skip argument 2, but print args 1, 3 and 4. You just have to use different printfs to do that.
--
Mats
Thanks. I always find myself writing a program, then getting tired and frustrated, missing stupid errors, soI go back to it with a fresh mind, solve the problem, and then just wanna keep adding and adding more and more to my program, and the cycle begins again. :)Quote:
Originally Posted by master5001
BTW, my program is making realy good progress (In large part due to the excellent helpers here!) and I almost have it finished. When I do, I want to make a GUI for it, and post it on my website, so I'll keep y'all posted.
Thanks, number two sounds like the best option for me, in fact this is exactly what I want, cheers.Quote:
There are a few ways to solve this problem. Simplest is to set it to '\0' and then check if it's '\0' - in that case, don't print it [putting a '\0' there will make string zero-length, becasuse sprintf isn't clever enough to know that you don't want a '\0' at the beginning of the string and thus make it an empty string].
The second option is to use a char array instead of a single char. An empty string "" will print as "nothing" in sprintf.
The third option is to use different format strings - only put the %c in the format string if it's actually needed - otherwise it will be ignored. Just beware that this ONLY works when it's the last argument(s) of sprintf that you want to skip, there is no way to skip argument 2, but print args 1, 3 and 4. You just have to use different printfs to do that.
--
Mats
That is basically how the game is played my friend. They say absense makes the heart grow fonder. When it comes to programming it makes the brain grow more observant and objective.Quote:
Originally Posted by bertazoid
very true :)
matsp: I tried using a string instead of a char within my switch statement, but couldn't get it to work. When I declared it outside the switch statement, and then initialized it within, I got the compiler error: "Incompatible types in assignment." When I tried to declare the string within the statement, I got the compiler error "String undeclared..." (pointing meto the line wheren I'm trying to print it. I tried testing this idea in a program of its own, within an if statement, and got the same results. Here's the two codes I used respectively:
Code:#include <stdio.h>
int main () {
int n=1;
if(n==1){
char string[]="+";
}
else{
char string[]="";
}
printf("%s", string);
return 0;
}
I don't understand why this doesn't work, since declaring/initializing other variable types within if/select statements seems fine.Code:#include <stdio.h>
int main () {
int n=1;
char string[5];
if(n==1){
string="+";
}
else{
string="";
}
printf("%s", string);
return 0;
}
Also I noticed with the original case, where I was declaring a char within the statement (On one of the three conditions), then used sprintf, I wasn't getting the hexagonal question mark at the front of the string, when I used this by itself in int main, but for some reason I do get it when I use it within a function of its own (with a string as an input parameter), and then call the fucntion in main....The function is of type int and returns 0, but it does apply this process to the input string - just wrongly so.
For the second, you can never (and by never, we mean never) assign anything to an array. Ever. Of any kind. You can initialize an array at declare time, but you can never assign to it. If you want something to be put into a char array, you can use strcpy.Code:#include <stdio.h>
int main () {
int n=1;
if(n==1){
char string[]="+"; /* This variable will go away when the block ends */
} /* poof! */
else{
char string[]=""; /* ditto */
} /* poof! */
printf("%s", string); /*what variable "string"? */
return 0;
}
thanks, I see, then I will try to use strcpy, and see if that works. p.s. did you mean to quote my second example? Any idea about the first?
I meant to quote your first example -- I'll edit the comments to make them pretty colors.
Thanks, I always prefer colourful responses :)
Then you probably would have really liked Quzah.