Thread: scanf

Code:

#include <stdio.h>
void main() {

    char operator,junk;
    float num1,num2,result;
    printf("enter two numbers\n");
    scanf("%f%f",&num1,&num2);
    printf("enter operator\n");
    scanf("%s", &operator);
    switch(operator) {
    case '+' : result=num1+num2;
        break;
    case '-' : result=num1-num2;
        break;
    case '/' : result=num1/num2;
        break;
    case '*' : result=num1*num2;
        break;
    default : printf("error in operator");
        
    }
    
    printf("%f\n",result);


}

hello all
whatever i enter for operator , the result is always default ? i guess i have issue at getting character with scanf. can anybody tell my mistake ?

Originally Posted by jimblumberg

Perhaps you need to use the correct format specifier for a char?

Edit: Also main() should be defined to return an int, not void.

is there important difference between void main and int main ?

Originally Posted by uryenugurkem

is there important difference between void main and int main ?

Yes one is "standard C" and the other is implementation defined

From the C standard:

5.1.2.2.1 Program startup

1 The function called at program startup is named main. The implementation declares no prototype for this function. It shall be defined with a return type of int and with no parameters:

Code:

         int main(void) { /* ... */ }

or with two parameters (referred to here as argc and argv, though any names may be used, as they are local to the function in which they are declared):

Code:

         int main(int argc, char *argv[]) { /* ... */ }

or equivalent;¹⁰⁾ or in some other implementation-defined manner.

Footnotes
10) Thus, int can be replaced by a typedef name defined as int, or the type of argv can be written as char ** argv, and so on.

So if you want to write C that will work on a range of compilers or machines then you should stick to one of the two ways to implement main defined by the standard

Originally Posted by Hodor

Yes one is "standard C" and the other is implementation defined

From the C standard:


So if you want to write C that will work on a range of compilers or machines then you should stick to one of the two ways to implement main defined by the standard

thank you for your intention

Hey there
In my opinion since you only need a single character input to work with your switch block you should maybe try using the getChar() instead of the scanf("%s",...).
The point is instead of using a String, use a Character.
Hope this helps.
Cheers.