Simple counters not working in C - c

Question

I am new to C have come across a problem that I think some of you may have had in the past. I am trying to code a program that has the user input a bunch of grades and the program tells you how many A,B,C,D,Fs you have entered.
How ever, the problem is that my counter for the grades just wont work.
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include<stdint.h>
//MACRO
#define F_Range (0-49)
#define D_Range (50-59)
#define C_Range (60-69)
#define B_Range (70-79)
#define A_Range (80-100)
#define A_COUNTer
#define B_COUNTer
#define C_COUNter
#define D_COUNTer
#define F_COUNTer
//Function Prototype
void display(void);
int main(int argc, char** argv) {
{
float input, F_Counter, D_Counter, C_Counter, B_Counter, A_Counter;
printf("Total Number of grades 'A' (80-100) = %.2f",A_Counter);
//the rest of the displays would go here
do
{
fflush (stdin);
scanf("%f",&input); //Get input from user
if (input == F_Range);
{
F_Counter++;
}
if (input == D_Range);
{
D_Counter++;
}
if (input == C_Range);
{
C_Counter++;
}
if (input == B_Range);
{
B_Counter++;
}
if (input == A_Range);
{
A_Counter++;
}
}
while (input != 999);
//Exit
{
}
return 0;
}
}

Answer 1

ok so for start when using #define x y you simply say "change all the reference to 'x' with 'y'" so when you have
#define C_Range (60-69)
and then
if (input == C_Range );
it iterputes as
if (input == (60-69));
which makes no sense, plus you have the ";" at the end of the if statement which doesn't make sense either
instead use:
#define F_RangeLow 0
#define F_RangeHigh 49
and the if statement
if (input >= F_RangeLow && input <= F_RangeHigh )
now another thing you have to do is to initiate the counter with 0. that's because you want to stat counting from 0...
float F_Counter=0;
there is no need for 2 "{" at the start of the main
this is quite enough:
int main(int argc, char** argv) {
.
.
.
}

Answer 2

Your counter variables are uninitialized. So, they hold unknown values. So you have to change float input, F_Counter, D_Counter, C_Counter, B_Counter, A_Counter; to float input, F_Counter=0, D_Counter=0, C_Counter=0, B_Counter=0, A_Counter=0;

Answer 3

Your code has multiple major issues.
The first is that your Range macros don't expand to working code:
#define F_Range (0-49)
…
if (input == F_Range);
This expands to:
if (input == (0-49));
which is only true if input is -49. If you want to check if input is between 0 and 49, you'll have to do that explicitly:
if (input >= 0 && input <= 49)
Given your current level of understanding of C, it's probably best if you don't use macros for now. Leave them alone, write out code in full, and start using macros once you have a firm grasp of the language.
The following line:
printf("Total Number of grades 'A' (80-100) = %.2f",""A_Counter);
^^
has a stray pair of quotation marks. (Does this even compile?)
Additionally:
You've got a semicolon at the end of the if statement mentioned above, which makes it not work correctly.
Your counter variables are not initialized to zero.

Answer 4

float input, F_Counter, D_Counter, C_Counter, B_Counter, A_Counter;
In the main() context you are incrementing these values and none of them are initialized. You have undefined behavior when you have uninitialized vairables.
The values should be initialized like
float input =0,F_Counter=0;/* similarly for the rest */
Checking the range using the macros also needs to be fixed (0-49) doesn't mean you are checking the range from 0 to 49 . Comparison operators should be used in these cases.

Answer 5

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <stdint.h>
#define S_(x) #x
#define S(x) S_(x)
#define RANGE_S(x) S((x##_Range))
#define COUNTER(x) x##_Counter
#define DISP(x) \
printf("Total Number of grades '%c' %s = %d\n",\
CHAR(x), RANGE_S(x), COUNTER(x))
#define CHECK(var, x) atoi(S(x##_Range)) <= var
#define CHAR(x) *#x
#define F_Range 0-49
#define D_Range 50-59
#define C_Range 60-69
#define B_Range 70-79
#define A_Range 80-100
void display(void);
int main(int argc, char** argv) {
float input;
int COUNTER(A)=0, COUNTER(B)=0, COUNTER(C)=0, COUNTER(D)=0, COUNTER(F)=0;
while(scanf("%f", &input)==1 && input != 999.f){
if (CHECK(input, A)){
++COUNTER(A);
} else if(CHECK(input, B)){
++COUNTER(B);
} else if(CHECK(input, C)){
++COUNTER(C);
} else if(CHECK(input, D)){
++COUNTER(D);
} else if(CHECK(input, F)){
++COUNTER(F);
}
}
DISP(A);
DISP(B);
DISP(C);
DISP(D);
DISP(F);
return 0;
}

Answer 6

Try Something Like This
#define F_Range(x) (x>=0 && x<=49)?true:false
#define D_Range(x) (x>=50 && x<=59)?true:false
#define C_Range(x) (x>=60 && x<=69)?true:false
#define B_Range(x) (x>=70 && x<=79)?true:false
#define A_Range(x) (x>=80 && x<=89)?true:false
AND
scanf("%f",&input); //Get input from user
if (F_Range(input));
{
F_Counter++;
}
else if (D_Range(input))
{
D_Counter++;
}
else if (C_Range(input))
{
C_Counter++;
}
else if (B_Range(input))
{
B_Counter++;
}
else if (A_Range(input))
{
A_Counter++;
}