C program not printing what I'd expect

Question

So I decided to learn C and using learn c the hard way. At any rate I tried editing one of the examples and the output isn't what I expected it would be. I call the program from the command line as e14 asd which "should" print: 'e' == 101 'a' == 97 's' == 115 'd' == 100

But, it doesn't print the 'd' line at all. The code I have is:

#include <stdio.h>
#include <ctype.h>

void print_letters(int argc, char *arg[])
{
    int i = 0;
    int j = 0;
    for(j = 0; j < argc; j++) {
        for(i = 0; arg[i] != '\0'; i++) {

            char ch = arg[j][i];
            printf("j is %d and i is %d\n", j, i);

            if(isalpha(ch) || isblank(ch)) {
                printf("'%c' == %d \n", ch, ch);
            }
        }
        printf("\n");
    }
}


int main(int argc, char *argv[])
{
    print_letters(argc, argv);
    return 0;
}

I'm assuming the problem has to do with the argv part but after looking around, I still have no idea what exactly is causing the 'd' not appear.

If someone could explain it to me it's be appreciated.

Thanks!

Answer 1

for(i = 0; arg[i] != '\0'; i++) {

should be

for(i = 0; arg[j][i] != '\0'; i++) {
//            ^^^

The loop exit condition should be iterating through the characters of a single command line argument but is actually iterating over the arguments.