Thread: Compile error with '||' operator.

  1. #1
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    Dec 2018
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    Compile error with '||' operator.

    Hey. Im trying to learn some C basics, I have only some python background and these vogue compiling errors on the silliest things are killing me. Like:

    Code:
    #include <cs50.h>
    #include <stdio.h>
    
    
    int main(void){
        char s1 = get_char("Give me a char: ");
    
    
        if (s1 == 'a' || 'A'){
            printf("OK",s1);
        }
    
    
        else if (s1 == 'd' || 'D'){
            printf("OK");
        }
    }
    Console output:

    ~/workspace/C/ $ make testC2
    clang -fsanitize=signed-integer-overflow -fsanitize=undefined -ggdb3 -O0 -std=c11 -Wall -Werror -Wextra -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable -Wshadow testC2.c -lcrypt -lcs50 -lm -o testC2
    testC2.c:7:19: error: use of logical '||' with constant operand [-Werror,-Wconstant-logical-operand]
    if (s1 == 'a' || 'A')
    ^ ~~~
    testC2.c:7:19: note: use '|' for a bitwise operation
    if (s1 == 'a' || 'A')
    ^~
    |
    testC2.c:9:21: error: data argument not used by format string [-Werror,-Wformat-extra-args]
    printf("OK",s1);
    ~~~~ ^
    testC2.c:12:24: error: use of logical '||' with constant operand [-Werror,-Wconstant-logical-operand]
    else if (s1 == 'b' || 'B')
    ^ ~~~
    testC2.c:12:24: note: use '|' for a bitwise operation
    else if (s1 == 'b' || 'B')
    ^~
    |
    3 errors generated.
    make: *** [testC2] Error


    I dont want to do bitwise op, I want to do a simple OR here and idk what is wrong.

  2. #2
    and the hat of int overfl Salem's Avatar
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    if (s1 == 'a' || s1 == 'A' )
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
    Registered User
    Join Date
    Dec 2018
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    4
    Crap, such a obvious mistake and somehow I didnt saw it. Thanks a lot sir.

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