Thread: if / else if / else statement not functioning properly

I'm having a very peculiar problem with my if / else if / else statement block. Certain inputs seems to be accessing multiple parts of the block, and some statements don't seem to be working at all. Here is my code:

Code:

int cc;
    ii = 0;
    for(cc = 0; cc < 1; cc--) { // infinite loop
        fgets(aa[ii], LINE_SZ, stdin);  // LINE_SZ = 90

        if(strlen(aa[ii]) == 1) // WORKS
            exit(0);

        if(strlen(aa[ii]) > 80) {

            fprintf(stderr, "Inside > 80\n");   
    
        } else if(aa[ii][0] == '<') {
            fprintf(stderr, "Inside <");

            // pop
            if(ii == 0) {
                fprintf(stderr, "Empty stack.\n");
            } else {
                printf("ii: &#37;d", ii);
                fprintf(stdout, aa[ii-1]);
            }

        } else if(aa[ii][0] == '>') {
            fprintf(stderr, "Inside >\n");

            // push
            if(ii == stackSize) {
                fprintf(stderr, "Full stack.\n");
            } else {
                strcpy(aa[ii], aa[ii]+1);
                ii++;
            }

        } else {

            // bad input
            fprintf(stderr, "Inside else - Bad input.\n");

        } 
                
    }

Even if my input line (aa[ii]) is over 80 chars long, it displays "Inside > 80" but then still goes to the else statement and displays "Inside else - Bad input."

but then still goes to the else statement and displays "Inside else - Bad input."

... on the next iteration, perhaps?

What do you mean? I only enter one line of input in the test.

Ah, but your loop is an infinite loop. Incidentally, since you never use cc, you could use for ( ;; ) if you really want an infinite loop.

Still, why not print cc to check which iteration of the loop you are in?

I include fflush(stdin) inside my if statement checking for over 80 chars, and it seems to work now.

You have the right idea, but the wrong implementation. Read the FAQ on Why fflush(stdin) is wrong.

> strcpy(aa[ii], aa[ii]+1);
Very few standard C functions are guaranteed to work on overlapping memory.

And, this is not infinite - just VERY LONG:

Code:

for(cc = 0; cc < 1; cc--) { // infinite loop

It may be infinite for the purposes of this code, but it will run out after it wraps around to positive numbers. If what you want is an infinite loop, there are four options, listed here in the order I would recommend using them:

Code:

// 1
  for(;;) ... 

// 2
  while(1) ...

// 3 
  do { ... } while(1);

// 4
Label:
  ... 
  goto Label;     // Not really a good option in most cases.

--
Mats