CODEWITHSUNDEEP
c
user2712068
user2712068

Reputation: 79

Char data type arithmetic expression

int main()

{

        char a = 'P';  

        char b = 0x80;  

        printf("a>b  %s\n",a>b ? "true":"false");  

        return 0;

}

Why does it evaluates to true?

Upvotes: 0

Views: 109

Answers (1)

Eric Postpischil
Eric Postpischil

Reputation: 224310

On your system, char is signed. It is also eight bits, so 0x80 overflows what a signed 8-bit integer can represent. The resulting value is -128. Since P is some positive value, it is greater than -128.

C permits the char type to be signed or unsigned. This is a special (annoying) property, unlike other integer types such as int. It is often advisable to explicitly declare character types with unsigned char so that the behavior is more determined rather than implementation-dependent.

Upvotes: 10

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