Keywords Keywords are predefined, reserved words used in programming that have special meanings. ex:- int money; Here, int is a keyword that indicates money is a variable of type int (integer). Identifiers Identifier refers to name given to entities such as variables, functions, structures etc. Variables In programming, a variable is a container (storage area) to hold data. ex:- int playerScore = 95; Here, playerScore is a variable of int type Constants If you want to define a variable whose value cannot be changed, you can use the const keyword. ex:- const double PI = 3.14; Data Types Data types are declarations for variables.This determines the type and size of data associated with variables. Input Output (I/O) use scanf() function to take input from the user, and printf() function to display output to the user #include <stdio.h> int main() { int a; float b; printf("Enter integer and then a float: "); // Taking multiple inputs scanf("%d%f", &a, &b)...