This is c++

This is one of the practice questions I am faced with :

Fill in the blank, so that this code sums only the high temperature!

// 0 is high, 1 is low

the problem is sum=0;

for (k=0; k<50; k++)

for (j=0; j<7; j++)

sum= sum + _______________

My answer is sum= sum+j++,and J++

I have been told this is incorrect

I have been looking at this code and I do not see enough information to answer this question There aren't any real temps. Please tell me what you think