So, it looks like you've been given some pseudo code to translate into code.
These zero_count minus_sum plus_sum are the names of the variables they want you to use to store these particular quantities. zero_count stores how many times x had a zero input. minus_sum stores the sum of all the negative inputted values of x. Finally, plus_sum stores the sum of all the positive inputted values of x. The rest of the statement is in English, so there should be no trouble understanding that.
When I mean "store", I mean how a variable in a C++ program is used to store data.
For instance:
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int main()
{
int x = 0; //here, x stores the value 0
bool b = true; //here, b stores the boolean value true
x++; //now, x stores the value 1
int zero_count = 0; //here, zero_count stores the value 0
return 0; //end of program
}