#include #include int main() { char input_char; int line_count = 0; while (1) { int read_result = scanf("%c", &input_char); if (read_result == EOF) { break; } if (islower(input_char)) { printf("%c", toupper(input_char)); } else if (isupper(input_char)) { printf("%c", tolower(input_char)); } else if (input_char == '\n') { line_count++; printf("%c", input_char); } else if (isprint(input_char)) { // Print visible characters as they are printf("%c", input_char); } } printf("%d\n", line_count); return 0; }