help with is digit

hello,
i'm not really sure if the problem lies in isdigit, what I do know is that it isn't doing it's job.

Code:

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char ErrorControl(char op,char line1[],char line2[],char line3[],char line4[],char line5[]){
    bool sure=true;
    int op_int,times=0;
      while(sure){
          op_int=op -'0';
          printf("%d",op_int);
         if((isdigit(op)) || (op_int>10)){
                          printf("test");
                          sure=false;
                          }
          else {
                printf("\nInvalid Option!\nInput option: ");
                scanf("%c",&op);
                fflush(stdin);
                times++;
                if(times==3) {
                            system("cls");
                            times=0;
                            }
                printf("%s %s %s %s %s",line1,line2,line3,line4,line5);
              }
          }
          return op;
}

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this is basicly a small function I made to see if the user input is what I expected. in that if, i change the bool to false, which should cause it to exit the while.
I ran out of ideas of what could cause this...

Thanks

How does it not work?

How did you #define "true" and "false"?

Quote:

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Originally Posted by MK27

How did you #define "true" and "false"?

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uhm what do you mean? they're keywords.

Quote:

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Originally Posted by sightl3ss

uhm what do you mean? they're keywords.

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They are not keywords. I assumed that you included <stdbool.h>. Did you?

By the way, fflush(stdin) results in undefined behaviour, and you could be a little more consistent with your indentation, but good to see that you posted code in code tags :)

Quote:

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Originally Posted by sightl3ss

uhm what do you mean? they're keywords.

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Sorry, I was unaware of <stdbool.h>.

Can you describe the problem in better detail? Are you saying that "test" prints out and then the loop happens again anyway? Or "test" does not print?

Quote:

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Originally Posted by laserlight

They are not keywords. I assumed that you included <stdbool.h>. Did you?

By the way, fflush(stdin) results in undefined behaviour, and you could be a little more consistent with your indentation, but good to see that you posted code in code tags :)

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i haven't included stdbool.h, they're keywords, i'm not sure it's because of the compiler i'm using? i'm using dev c bloodshed

and i know i wasn't very clear, i'm sorry. i'm going to review this over(having an headache right now..) and then i'll post the problems i encounter.(i kind of forgot..)
thank you for your answers

edit: i didn't include the whole code because it's a lot of lines(probably a lot less than what you're used to see here, still)
anyways im using these libs:
#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<windows.h>
#include<ctype.h>

Quote:

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Originally Posted by sightl3ss

i haven't included stdbool.h, they're keywords, i'm not sure it's because of the compiler i'm using? i'm using dev c bloodshed

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The Bloodshed Dev-C++ IDE comes with the MinGW port of gcc, which does not have such an extension that true and false are recognised as keywords. More likely you are compiling as C++ instead of C.

Quote:

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Originally Posted by sightl3ss

edit: i didn't include the whole code because it's a lot of lines(probably a lot less than what you're used to see here, still)

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The best option is for you to describe the problem as well as you can. If that doesn't work, you could post the whole thing and someone *might* test it, but on the other hand, they might not. So try to describe the problem.

Code:

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if((isdigit(op)) || (op_int>10)){

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will be true if op is from '0' to '9', or pretty much any character above ':' which includes

Code:

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