Using arrays to compare char - c

Question

I'm coding this pattern game, but I am having difficulties in storing the previous input of the users "uno" and "dos" to a array so it can be compared, if same it will ask for another input which has not been picked. Example of This
Round 1:
Player 1 Inputs : -> A
Player 2 Inputs : -> B
Valid
Round 2:
Player 1 Inputs : -> L
Player 2 Inputs : -> V
Valid
Round 3:
Player 1 Inputs : -> A (Invalid Already been used)
enter char again
That above is an example i am trying to achieve. I will post the code below. I would appreciate the help very much.
#include <stdio.h>
#include <string.h>
#define SWITCH(_g0,_g1) \
(_g0 << 8) | (_g1 << 0)
#define CASE(_g0,_g1) \
case SWITCH(_g0,_g1)
intgetval(const char *prompt)
{
char *cp;
char buf[100];
int val;
while (1) {
printf("%s: ",prompt);
fflush(stdout);
cp = fgets(buf,sizeof(buf),stdin);
// handle end of file
if (cp == NULL) {
val = -1;
break;
// get the first char on the line
val = buf[0];
if (val != '\n')
break;
}
return val;
}
int main ()
{
int i = 0;
int roundCount = 1;
int pos = 0;
int over = 0;
int f = 1;
char G[9];
char uno,dos;
printf("Game Start!\n");
do {
printf("Round %d!\n", roundCount++);
printf("Input selection upon prompt.\n");
printf("Player 1: ");
scanf(" %c", &uno );
printf("Player 2: ");
scanf(" %c", &dos);
if()
//printf("DEBUG: %2.2X %2.2X\n",G[0],G[1]);
switch (SWITCH(uno,dos)) {
CASE('L','V'):
CASE('V','S'):
CASE('S','P'):
CASE('P','R'):
CASE('R','L'):
CASE('R','S'):
CASE('P','V'):
CASE('S','L'):
CASE('V','R'):
CASE('L','P'):
f++;
pos--;
printf("Uno Wins! Pos[%d]\n\n", pos);
break;
CASE('R','P'):
CASE('L','R'):
CASE('R','V'):
CASE('P','S'):
CASE('P','L'):
CASE('S','R'):
CASE('S','V'):
CASE('L','S'):
CASE('V','P'):
CASE('V','L'):
f++;
pos++;
printf("Dos Wins Pos[%d]!\n\n", pos);
break;
CASE('R','R'):
CASE('P','P'):
CASE('S','S'):
CASE('L','L'):
CASE('V','V'):
f++;
pos = pos;
break;
}
if (pos == -3 || pos == 3) {
printf("Game over\n");
break;
}
if (f == 5 && pos != -3 && pos != 3) {
switch (SWITCH(uno,dos)) {
CASE('L','V'):
CASE('V','S'):
CASE('S','P'):
CASE('P','R'):
CASE('R','L'):
CASE('R','S'):
CASE('P','V'):
CASE('S','L'):
CASE('V','R'):
CASE('L','P'):
printf("Uno:Wins!\n");
break;
CASE('R','P'):
CASE('L','R'):
CASE('R','V'):
CASE('P','S'):
CASE('P','L'):
CASE('S','R'):
CASE('S','V'):
CASE('L','S'):
CASE('V','P'):
CASE('V','L'):
printf("Dos Win!\n");
break;
}
}
} while (f < 5);
return 0;
}
im trying to implement a for loop for this but it wouldn't work , i am not getting the result that i want, adding this code. I would appreciate it if you would rewrite the code with this loop or if there is any other way please tell me how.
for ( i = 0; i < sizeof(useduno); i++)
{
if (uno == useduno[i]) // where useduno is the array, where uno is to be stored, so it cannot be used again
{
printf("You already used the letter. Use another letter: ");
scanf(" %c", &uno);
}
}