18640
Question:
I wrote a test program which should take in a 3x3 matrix of characters and output the entered matrix. However, I have to enter 4 lines in order for the program to produce the corresponding matrix. I have looked up problems on the scanf function, but none of the solutions I tried seemed to work...Could you help me out with this?
My code:
#include <stdio.h>
#include <stdlib.h>
int main(void) {
char a[3][3];
int i,j;
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
{
scanf("%c",&a[i][j]);
}
scanf("\n");
}
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
{
printf("%c",a[i][j]);
}
printf("\n");
}
system("PAUSE");
return(0); }
Answer1:scanf("%c",...) get the whitespaces and the \n. You can solve it in many ways:
If you read like a b c
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
{
scanf("%c",&a[i][j]);
cin.get(); //Get the spaces after each character and the \n at the end of each line
}
}
or you can simple use cin (read char/string inputs with scanf is always a problem)
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
{
cin >> a[i][j];
}
}
if you are reading like abc, you only have to substitute your scanf("\n") for a cin.get()
@João Menighin's answer surely works. If you want to avoid c++, this would work:
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
{
scanf(" %c",&a[i][j]);
}
}
Although it would ignore ALL whitespace: both abc and a b c would be interpreted to be equivalent.
try adding a white space in your scanf right after the "
scanf(" %c",&a[i][j]);
I had the same problem in a two-dimension matrix and it worked for me. I have no idea why though!!! I just spent 1 hour in front of my laptop trying different things...
Answer4:Have tried your and IT WORKED. Although, I did make a few changes per comments:
#include <stdio.h> // added, but that shouldn't matter
main()
{
char a[3][3];
int i,j;
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
{
scanf("%c",&a[i][j]);
}
//scanf("\n"); // not necessary, see below
}
for(i=0;i<3;++i)
{
for(j=0;j<3;++j)
{
printf(" %c",a[i][j]);
}
printf("\n");
}
return(0);
}
Compiled and ran this code on Eclipse/Microsoft C Compiler and entered series of characters followed by enter.
abcdefghi
a b c
d e f
g h i
The point of confusion might be that scanf pulls the data from a console buffer. Typically, (although you can work around this) that buffer is returned to your program when you press enter. Also, the format specifier of %c also accepts blanks. Thus, I tried a second run with the following input and output.
a b c d e
a b
c
d e
You can tell the spaces were read and stored as well as the letters.
Hope this helps.
