In the C programming language, placeholders and control characters are used to format and control the output of text in console-based programs. They are special characters or sequences of characters that have specific meanings. Here are the placeholders and control characters commonly used in C: 1. Placeholders: - %d: Used to display signed integers. Example: printf("The value is %d", 10); - %u: Used to display unsigned integers. Example: printf("The value is %u", 10); - %f: Used to display floating-point numbers. Example: printf("The value is %f", 3.14); - %c: Used to display characters. Example: printf("The character is %c", 'A'); - %s: Used to display strings (sequence of characters). Example: printf("The string is %s", "Hello"); - %p: Used to display memory addresses (pointers)...