what does this for loop do in c ? for(; j; printf("%d %d",i,j)) :   

      #include <stdio.h>
    
    int main(void) {    
        int i=1,j=1;
        for (; j; printf("%d  %d",i,j))
        j = i++<=5;
    	return 0;
    }
**output-**

2  13  14  15  16  17  0

can anyone Explain,what is happening inside the loop!. This question is asked by Zoho Cooperation in the interview process.