What is a keyword?

Keywords are the reserved word’s in a programming language. These are predefined in a programming language and has different mean for the compiler. These keywords can’t be used as a user-defined program identifier.

List of keyword defined in the c language

Example :

#include <stdio.h>      
int main() {
  int a;
  double x;
  return 0;
}

What is Data Type?

• Data types are used to define the variable and function in a program to store the value of different sizes or types.
• The data type is useful to save memory space.
• We have different datatype to store the different sizes of data. 

List of dataTypes with respect to their sizes

Example:

#include <stdio.h>      
int main() {
  int a;
  printf("size of int= %d bytes\n", sizeof(a));
  return 0;
}