CODEWITHSUNDEEP
cwhile-loopc99c89
How Chen
How Chen

Reputation: 1370

coding style aginst warning check

During clean compile warning, I met following code:

char *strcpy(char *dest, char *src)
{
    unsigned int i;

    while( dest[i] = src[i] )//assignment in condition
        i++;

    return dest;
}

the base function of the code should be OK, but compiler warn that the assignment in condition, does this part of code have any potential risks? if this kind of warning need be cleaned?

Upvotes: 3

Views: 75

Answers (2)

user3125367
user3125367

Reputation: 3000

All kinds of warnings need to be cleaned.

This warning was introduced because = and == is often confused by programmers (hello, Pascal!), and your intent may be explicitly stated by adding parentheses around assignment expression:

if ((x = y)) // no warning

Upvotes: 4

Barmar
Barmar

Reputation: 782106

No, you don't need to fix this.

The reason for the warning is that sometimes people mistakenly type = when they mean ==, e.g.

while (response = 'n')

An assignment in a conditional is more likely to be a mistake like this than an assignment whose value you want to test, so the compiler warns about it. You can silence the warning by wrapping the assignment in a test:

while ((dest[i] = src[i]) != 0)

On the other hand, I recommend that you always put the body of a while or if inside {}, even if it's just one statement. See Why is it considered a bad practice to omit curly braces?

You also need to initialize i:

unsigned int i = 0;

Upvotes: 3

Related Questions