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Since printf of a string works with an address in input, why printf does not accept just "argv"

int main(int argc, char **argv){
    printf("argv: %s\n",argv); // does not work and prints random stuff
    printf("*argv: %s\n",*argv); // works and prints ".a.out"

}

I test with:

./a.out nop

My confusion is this:

"argv" variable in the second line has the address of the first char of "./a.out".

"*argv" variable in third line is the first char of "./a.out".

So why printf("argv: %s\n",argv); to only print "./a.out" does not work?

I know that it's wrong, but I don't know why.

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Allexj Avatar asked Dec 19 '21 11:12

Allexj


1 Answers

argv is a pointer to a pointer. It means it "points" to addresses, not directly to characters.

So at address argv, other addresses are stored, not strings. If you want to access the first string, you have to use the address of it, which is either *argv or argv[0].

I don't know if it's clear enough, don't hesitate to ask for more clarifications.

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lfalkau Avatar answered Oct 21 '22 14:10

lfalkau