Why is the output 6723 and not 7632 ?

Question

#include<stdio.h>

int r(){
 static int num=9;
return num--;
}

int main() {
    
for(r();r();r()) {
printf("%d%d",r(),r());
};
return 0;
}

Why is the output 6723 and not 7632?

Comments

check 2019 gate question paper, You will find exact question with values change.

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@Shaik Masthan Sir evaluation order of parameter in printf function is undefined, right?

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@raja11sep yes order of evaluation of parameters is undefined in C.