IF - 条件与char比较不在C中工作

Question

I really don't know what's the mistake. It seems to be right, doesn't it?

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

int main(int argc, char *argv[])
{
   char op;

   printf("Type in operator (+,-,/,*):");
   scanf("%i",&op);

   if(op == '+')
   {
      printf("You entered a plus");
   }

   system("pause"); 
   return 0;
}

I expected it to print "You entered a plus" when entering a +. It does not.

I'm kinda new to C. Thanks in advance :)

Answer 1

The if condition is fine. The problem is the scanf() format, which should be

scanf("%c",&op);

( %i reads an integer whereas %c reads a char .)

Answer 2

scanf("%i", &op);

You are expecting an integer. So, when you write a character and press <Enter> , scanf fails (you can check its return value to see it):

if (scanf("%i", &op) != 1)
{
    /* Treat the error. */
}

Use rather %c format in scanf to read characters:

scanf("%c", &op);

Answer 3

Your problem is with wrong format specifier

//In scanf instead of 
scanf("%i",&op);
// you have to provide 
scanf("%c",&op);

%i use for reading integer whereas %c use for reading char.