Let's first of all get a little deeper into printf. You can print a line end with \n, and generally escape special characters with \ as well. \" prints " and \ . We can use format strings to print variables e.g. printf("n = %d \n",n); assumes that n is an integer and prints its value. To print characters we can use %c - you can easily look up the other formats.

#include <stdio.h> #include <stdlib.h> int main() { printf("special character magic \" or \\ \n"); int n = 42; printf("n = %d \n",n); char c = 'A'; tools_log(); printf("c = '%c' \n",c); return EXIT_SUCCESS; }