I was asked to do a work in C when I'm supposed to read from input until there's a space and then until the user presses enter.
If I do this:
scanf("%2000s %2000s", a, b);
It will follow the 1st rule but not the 2nd.
If I write:
I am smart
What I get is equivalent to:
a = "I";
b = "am";
But It should be:
a = "I";
b = "am smart";
I already tried:
scanf("%2000s %2000[^\n]\n", a, b);
and
scanf("%2000s %2000[^\0]\0", a, b);
In the 1st one, it waits for the user to press Ctrl+D (to send EOF) and that's not what I want.
In the 2nd one, it won't compile. According to the compiler:
warning: no closing ‘]’ for ‘%[’ format
Any good way to solve this?
scanf
(and cousins) have one slightly strange characteristic: any white space in the format string (outside of a scanset) matches an arbitrary amount of white space in the input. As it happens, at least in the default "C" locale, a new-line is classified as white space.
This means the trailing '\n'
is trying to match not only a new-line, but any succeeding white-space as well. It won't be considered matched until you signal the end of the input, or else enter some non-white space character.
To deal with this, you typically want to do something like this:
scanf("%2000s %2000[^\n]%c", a, b, c);
if (c=='\n')
// we read the whole line
else
// the rest of the line was more than 2000 characters long. `c` contains a
// character from the input, and there's potentially more after that as well.
scanf("%2000s %2000[^\n]", a, b);
use getchar and a while that look like this
while(x = getchar())
{
if(x == '\n'||x == '\0')
do what you need when space or return is detected
else
mystring.append(x)
}
Sorry if I wrote a pseudo-code but I don't work with C language from a while.
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
int main(void)
{
int i = 0;
char *a = (char *) malloc(sizeof(char) * 1024);
while (1) {
scanf("%c", &a[i]);
if (a[i] == '\n') {
break;
}
else {
i++;
}
}
a[i] = '\0';
i = 0;
printf("\n");
while (a[i] != '\0') {
printf("%c", a[i]);
i++;
}
free(a);
getch();
return 0;
}
I am too late, but you can try this approach as well.
#include <stdio.h>
#include <stdlib.h>
int main() {
int i=0, j=0, arr[100];
char temp;
while(scanf("%d%c", &arr[i], &temp)){
i++;
if(temp=='\n'){
break;
}
}
for(j=0; j<i; j++) {
printf("%d ", arr[j]);
}
return 0;
}
Sounds like a homework problem. scanf() is the wrong function to use for the problem. I'd recommend getchar() or getch().
Note: I'm purposefully not solving the problem since this seems like homework, instead just pointing you in the right direction.
#include <stdio.h>
int main()
{
char a[5],b[10];
scanf("%2000s %2000[^\n]s",a,b);
printf("a=%s b=%s",a,b);
}
Just write s in place of \n :)