/* PBXA64 handbook-style C text example: tab_expansion.
 * calculate visual columns after tab expansion. This source deliberately keeps every transformation visible
 * instead of hiding it behind library calls, making it useful for tracing.
 */
int main(void) {
    char s[] = "a\tb"; int i = 0, column = 0; for (i = 0; s[i] != 0; ++i) { if (s[i] == '\t') column += 4 - (column % 4); else ++column; } return column == 5 ? 0 : 1;
}

/* Discussion: inspect the loop bounds, byte classification, and final return
 * value. The bounded-C frontend currently records CIR0200 for all C source;
 * this example remains a real handbook program for the public C surface once
 * that frontend gate is restored. */
