scanf character - Printable Version

scanf character - Printable Version

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scanf character - Xe.4 - 12-20-2012

Guys, I have this strange problem in C, I can't figure out the problem. I want to make a small calculator and it is like this:

Code:
float a,b,total;
    char op;
    printf("a= ");scanf("%f",&a);
    printf("op[+,-,*,/,%]= ");scanf("%c",&op);
    printf("b= ");scanf("%f",&b);

The rest are switch statement for each operator.

After I compiled and run it, it just skips the scanf statement for variable 'op' and goes on to scanf for value b. like this:

a= 56
op[+,-,*,/,%]= b=
...

Thanks.

:epic:

scanf character - Xe.4 - 12-20-2012

Guys, I have this strange problem in C, I can't figure out the problem. I want to make a small calculator and it is like this:

Code:
float a,b,total;
    char op;
    printf("a= ");scanf("%f",&a);
    printf("op[+,-,*,/,%]= ");scanf("%c",&op);
    printf("b= ");scanf("%f",&b);

RE: scanf character - H4R0015K - 12-20-2012

Code:
float a,b,total;
    char op;
    printf("a= ");scanf("%f",&a);
    printf("op[+,-,*,/,%]= ");scanf(" %c",&op); 
    printf("b= ");scanf("%f",&b);

after scanf(" leave a space then type %c",&op); now it will not get skipped i dont know why it is like this but i will let you know as soon as i come to know.

RE: scanf character - H4R0015K - 12-20-2012

Code:
float a,b,total;
    char op;
    printf("a= ");scanf("%f",&a);
    printf("op[+,-,*,/,%]= ");scanf(" %c",&op); 
    printf("b= ");scanf("%f",&b);

after scanf(" leave a space then type %c",&op); now it will not get skipped i dont know why it is like this but i will let you know as soon as i come to know.

RE: scanf character - Xe.4 - 12-20-2012

Thanks, that solved the problem. but I want to know the reason aswell . Biggrin

RE: scanf character - H4R0015K - 12-21-2012

%c format specifier requires a blank space before it because it start from a blank space or whitespace it does not store the blank space if it is not there it will skip the scanf fuction to solve this you can use %s which is string format specifier or leave a blank space before %c.

RE: scanf character - Xe.4 - 12-21-2012

Thank for explaining .

RE: scanf character - The Alchemist - 12-23-2012

Or, don't use scanf to input characters. Use getchar() instead...
And before inputting a character, always use fflush(stdin) to flush any unnecessary characters.

I'm not going into further details... They are simple...

RE: scanf character - H4R0015K - 12-23-2012

(12-23-2012, 04:09 PM)The Alchemist Wrote: Or, don't use scanf to input characters. Use getchar() instead...
And before inputting a character, always use fflush(stdin) to flush any unnecessary characters.

I'm not going into further details... They are simple...

i have read somewhere that getchar() are vulnerable and is recommended not to use it.