There are basically three types of C instructions.
1. Type Declaration Instruction
Type Declaration Instruction : As its name suggests it is used to declare
 type of variables in C language. It is must that you have to declare the 
 type of variable before using it. And it is also must that these type 
 declaration instruction should be provided in the beginning of the program 
 (just after the main()).
2. Arithmetic Instruction
hese instructions are used to perform some arithmetic calculation within the 
program. It uses arithmetic operators like +, -, X, /, %, =, ++,–, +=,-+ etc.
3. Control Instruction
Like the name suggests, these instructions are used to control the flow of the
program execution. They maintain certain order in which program needs to be
executed , also there are four different types of control instruction 
have a happy programing