calculator with input string in its operation selection

Question

How to make calculator with input string in its operation selection?, i have tried but it doesn't work. My lecture assigned :)

printf("choose:");
scanf("%s", (char *) &choose);

switch(choose)
{
case 'tambah':
printf("Masukkan Nilai 1:");
scanf("%d", &x);
printf("Masukkan Nilai 2:");
scanf("%d", &y);
hasil = tambah(x,y);
printf("%d + %d = %d", x, y, hasil);
break;

case 'kurang':
printf("Masukkan Nilai 1:");
scanf("%d", &x);
printf("Masukkan Nilai 2:");
scanf("%d", &y);
hasil = kurang(x,y);
printf("%d - %d = %d", x, y, hasil);
break;

Your code is incomplete; in particular, it seems to be missing a main() function. Please edit your code so it's a [Minimal, Complete, and Verifiable](https://stackoverflow.com/help/mcve) example of your problem, then we can try to reproduce and solve it. You should also read [How to Ask](https://stackoverflow.com/help/how-to-ask). — H.S., Oct 30 '17 at 10:51
Why switch statement cannot be applied on strings? https://stackoverflow.com/questions/650162/why-switch-statement-cannot-be-applied-on-strings — Aditi Rawat, Oct 30 '17 at 10:56

Gnqz · Accepted Answer · 2017-10-30T11:54:05.777

Using string (considering you use strings since in your example you just put several chars into literal, which is supposed to be a char) directly in switch() statement in C is a terrible idea. I suggest enuming the possible options and feed them in a strcmp in order to match your operation and branch accordingly.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

enum {
tambah = 0,
kurang = 1
};

int decodeLineType(const char* strAction)
{
  int i = 0;

  char acAllowedCodes[2][7] = {"tambah","kurang"};

  for(; i < 2; ++i)
  {
    if (strncmp(strAction, acAllowedCodes[i], strlen(acAllowedCodes[i])) == 0)
    {
      return i;
    }
  }

  return(-1);
}

int main()
{
    char choose[30] = {0};
    scanf("%s", choose);
    switch(decodeLineType(choose))
    {
       case tambah :
         /* some logic here*/
       break;
       case kurang :
         /* some logic here*/
       break;
       default:
       break;
    }
    return(0);
}

Offtopic: Also please consider using english for all labels and variable names in your program when you're about to seek guidance in an international forum.

calculator with input string in its operation selection

1 Answers1