// *** before: ***
/* C89: every declaration stands at the top of a block, before the
first statement, and a comment is only the slash-star kind */
int i;
int sumOld;
double averageOld;
sumOld = 0;
for (i = 1; i <= 4; i++)
sumOld += i;
averageOld = sumOld / 4.0;
/* averageOld is 2.5 */
printf("averageOld is %g\n", averageOld);
// *** in version C99: ***
//a variable is declared where its value first appears
int sum = 0;
for (int i = 1; i <= 4; i++) //this i lives only inside the loop
sum += i;
double average = sum / 4.0;
//average is 2.5
//and the // comment itself is new in C99 as well
printf("average is %g\n", average);