Thread: program explanation

Code:

#include <stdio.h>

void main()
{
	int a,b;

	for(a=0;a<6;++a){
		for(b=0;b<=a;++b)
			putchar('*');
			putchar('\n');
	}
}

This generates the figure:
*
**
***
****
*****
******
Could someone dissect each for statement and the entire loop as well?
What I don't get is how it knows to print just 1 * first, then 2 ...
Sorry for being such a newbie ... and thanks.

hmm, read a book on the for statement, then take about 5 minutes to look at the tiny piece of code and you will figure it out and have a better understanding of for loops!

Your indentation is lying, the indentation that reflects what is actually happening is like this:

Code:

#include <stdio.h>

int main(void) /* main returns int, not void */
{
    int a,b;
    for (a = 0; a < 6; ++a)
    {
        for (b = 0; b <= a; ++b)
            putchar('*'); /*only one statement in the inner for, because there are no braces */
        putchar('\n');
    }
    return 0;
}

Make more sense now?

CWR - thanks ... and not really, but i copied it down and i'll analyze it.

rockytriton - what book would you suggest? for beginners and with lots of sample programs and exercises i can study?

any book that contains the phrases "c++" and "beginner", or like sunny suggest, use a tutorial, but not all tutorials will actually explain how things work well.

Work through the code in your head, going through each line and seeing what happens to a and b. If that is too difficult, add some diagnostic printf's to show the values of a and b, or run it through a debugger.