Turbo C - Scanf to only accept one character

Question

I want to make scanf only accept one character, but I am not familiar with the method of doing so. can anyone help me here.

here is my current code:

void push(S *stack){
      char e;
      S temp;
      temp=malloc(sizeof(struct stack));
      if(!temp){
         printf("Failed\n");
         return;
     }
     printf("Input value: \n");
     scanf(" %c", &e);
     if(('a'<=e && e<= 'z') || ('A'<=e && e<= 'Z')){
         temp->data=e;
         if(*stack == NULL){
            temp->next = temp->prev = NULL;
            *stack=temp;
         } else {
           temp->next = *stack;
           (*stack)->prev = temp;
           temp->prev = NULL;
           *stack=temp;
         }
    printf("Success %c", e);     
    }else{
        printf("Failed %c", e);
    }  
}

Forgot to mention:

if i were to input "abc" it will be pushed in the stack as a,b and c. though it is correct i was hoping to have a way to nullify the input and only accept it if its only a single character, if this is possible of course? if not then i will stick with the current one, was just hoping for a better implementation. thank you

Answer 1

Try this:

int ch;
...
printf("Input value: \n");
scanf(" %c", &e);

while( (ch = getchar()) != '\n' && ch != EOF);   // To eat up all the characters left behind by scanf call including '\n'.  

scanf reads the first character you typed in to e. The rest of the characters left behind in the buffer is read one by one to ch by the getchar in while loop until it reads \n. When it reads \n then condition becomes false and the loop is terminate. Now your buffer is empty.

Answer 2

Add one more line of code after scanf

 scanf(" %c",&e);
 getchar();

The getchar reads the new line, when you press enter after you type the character. Hope this helps.

Answer 3

And if you just dont want your program to wait for an enter after typing the character, use getch() defined in <conio.h>

c = getch();