Xcode 5 Start to Finish: iOS and OS X Development

Compiling

Fortunately, you have a computer to keep track of such things. A compiler is a program that takes source files and generates the corresponding streams of machine-level instructions. Consider this function, that calculates two averages and sends them back to the caller through a results struct:

Click here to view code image

void calculate_stats(Results * results){    int     n = 0, nScanned = 0;    double  sum_X, sum_Y;    sum_X = sum_Y = 0.0;    do {        double      x, y;        nScanned = scanf("%lg %lg", &x, &y);        if (nScanned == 2) {            n++;            sum_X += x;            sum_Y += y;        }    } while (nScanned == 2);    Results     lclResults = { .avg_X = sum_X/n#if CALCULATE_AVG_Y        , .avg_Y = sum_Y/n ...