Loop using goto control statement, but it skips one command - c

Question

I just learned C programming. Now, I am trying to perform looping
using the goto control statement, but I just faced a problem when I
use variable char.
#include <stdio.h>
char score;
int main(){
loop:
printf("Please Input Your Score : ");
scanf("%c", &score);
switch(score){
case 'A' :
printf("Nilai Anda Baik");
break;
default :
printf("Nilai Anda Salah");
goto loop;
}
return 0;
}
The problem is if I input the wrong score such as 'B', it will print "Nilai Anda Salah" and then automatically print again "Please Input Your Score: Nilai Anda Salah" one time. After that print again "Please Input Your Score: " and then I can input again the score.
I don't know why it is skipping the scanf command.

Answer 1

Use the following format specifier
scanf(" %c", &score);
^^^
to skip the new line characters between entered characters.
Also according to the C Standard function main without parameters shall be declared like
int main( void )
Take into account that it is a bad idea to use the goto statement. Also there is no need to declare the variable score as global.
The program can look the following way
#include <stdio.h>
int main(void)
{
char score = 'A';
do
{
printf( "Please Input Your Score : " );
scanf( " %c", &score );
switch( score )
{
case 'A' :
puts( "Nilai Anda Baik" );
break;
default :
puts( "Nilai Anda Salah" );
break;
}
} while ( score != 'A' );
return 0;
}