#include <stdio.h>

int main(void) {

  float a, b;
  char ch;

  printf("Vyberte operaci pomoci prvniho pismena:\n");
  printf("(S)citani, (O)dcitani, (N)asobeni nebo (D)eleni?\n");

  do {
    ch = getchar();
  } while(ch!='S' && ch!='O' && ch!='N' && ch!='D');

  printf("Napiste prvni cislo: ");
  scanf("%f", &a);

  printf("Napiste druhe cislo: ");
  scanf("%f", &b);

  switch(ch) {
    case 'S': printf("%f + %f = %f\n", a, b, a + b);
      break;
    case 'O': printf("%f - %f = %f\n", a, b, a - b);
      break;
    case 'N': printf("%f * %f = %f\n", a, b, a * b);
      break;
    case 'D': if(b!=0) printf("%f / %f = %f\n\n", a, b, a / b); else printf("MATH ERR: Deleni nulou!\n");
  }

  return 0;
}