Work With Char Using If else in C Language - c

Question

Whenever I use if Statement to make a decision by comparing a character using char and %d, then it results in false always.
example:
#include<stdio.h>
#include<conio.h>
int main(void) {
int a, b;
float r;
char op;
printf("Enter 1st num : ");
scanf("%d", & a);
printf("Enter 2nd Num : ");
scanf("%d", & b);
printf("Enter Operator ( +, - , * , /) : ");
scanf("%c", & op);
if (op == '+') {
r = a + b;
printf("Ans = %f", r);
getche();
} else if (op == '-') {
r = a - b;
printf("Ans= %f", r);
}
//same as above for remaining 2 functions of * and /
else
printf("Error Occurred");
}

Answer 1

After typing the second number you press enter, right? %c in scanf accepts the first character it finds, so it returns the line break character corresponding to you pressing enter.
An easy fix is to add a space character before %c. It makes scanf skip any whitespace.
scanf(" %c",&op);
From the scanf documentation (http://www.cplusplus.com/reference/cstdio/scanf/):
Whitespace character:
The function will read and ignore any whitespace characters encountered before the next non-whitespace character (whitespace characters include spaces, newline and tab characters -- see isspace). A single whitespace in the format string validates any quantity of whitespace characters extracted from the stream (including none).

Answer 2

Because %d ignore white-spaces and special characters. White-spaces and special characters are chars. So, %c has to take white-spaces and special characters as inputs.
You can test the output of the code below.
#include <stdio.h>
int main(void)
{
char p = 'w';
char l = 'x';
char t = 't';
printf("Give one, two or three chars: ");
scanf("%c%c%c", &p, &l, &t);
printf("p = %c, l = %c, t = %c \n", p, l, t); //
scanf("%c", &t);
printf("plt = %c%c%c \n", p,l,t);
return 0;
}