Callback function

/** $g++ callback.c -o callback ./callback Item 4 http://en.wikipedia.org/wiki/Callback_%28computer_science%29 */ #include /* LIBRARY CODE */ int traverseWith(int array[], size_t length, int (*callback)(int index, int item, void *param), void *param) { int exitCode = 0; for (int i = 0; i < length; i++) { exitCode = callback(i, array[i], param); if (exitCode != 0) { break; } } return exitCode; } /* APPLICATION CODE */ int search (int index, int item, void *param) { if (item > 5) { *(int *)param = index; return 1; } else { return 0; } } main() { /* (in another function) */ int index; int found; int array[] = {1, 2, 3, 4, 7, 10, 12, 15 }; int length = 6; found = traverseWith(array, length, &search, &index); if (found) { printf("Item %d\n", index); } else { printf("Not found\n"); } }