As part of performance testing using Load runner Learn C language

-> C is a structured programming language.
-> It is closely related to Assembled language.
-> It is easy to implement and produces efficient programs

Have a glance on variables,datatypes

Simple Programs using vuser load generator on C

Sample program in C

    #include<stdio.h> //
       // All the standard input files available at stdio library
    #inculde<conio.h> 
    // All the console input out functions available at conio library
    Global declaration; //Will be accessible for all the functions  
    // single line comment //Comments cannot be executed
    void main();
   //In c every program starts and end with main fun,it is starting of the program
    {   ->Function starts here 
   int a,b,c;
    a=10;b=20;
    c=a+b;
       printf("addition of a,b =%d,a);
       //printf prints the message on the screen
          // system needs to understand so %d used in printf
     //scanf(" ......................") ; ->scanf to accept the values at run time 
        getch();               //This function is used to get the character at run time.
     clrscr();          //this function is used to clear the screen
      return 0;        //To release the allocated memory                           
     }   

Sample C program in Load runner

  Action()
   {                                

   int a,b,c;
   a=10;b=20;
     lr_output_message("the value of a=%d,a");
    // lr_output_message is predefined fun prints the message on the screen
      lr_output_message("the value of b=%d,a");    
   c=a+b;     
   lr_output_message("the Addition of a,b=%d,c");     
   c=a-b;     
   lr_output_message("the Subtraction of a,b=%d,c");     
  c=a*b;     
   lr_output_message("the Multiplication of a,b=%d,c");   
  c=a/b;     
   lr_output_message("the Division of a,b=%d,c");          
   return 0;        //To release the allocated memory     

Rand():-
       -->    To Generate a random number in between any of the given range
       -->    A=rand()%8 will generate random values from 0 To 7;
       -->   Using the above function always the values starts from '0'

To Generate Random Value from desired numbers using Random function:
  If you want generate values from 31- 51 then the below random function need to use
           I.e   is rand()%21+31
To generate random value from 31- to 51 below is the formula
        Value=max-min+1

Sample program for arithmetical operations using desired random value

 Action()
   {                              

   int a,b,c;
   a=rand()%21+31;
    b=rand()%11+21;
     lr_output_message("the value of a=%d,a");
    // lr_output_message is predefined fun prints the message on the screen
      lr_output_message("the value of b=%d,a");    
   c=a+b;   
   lr_output_message("the Addition of a,b=%d,c");    
   c=a-b;   
   lr_output_message("the Subtraction of a,b=%d,c");    
  c=a*b;   
   lr_output_message("the Multiplication of a,b=%d,c");   
  c=a/b;   
   lr_output_message("the Division of a,b=%d,c");        
   return 0;        //To release the allocated memory   

Conditional statements:
If a particular condition is true then it will execute the program other wise it will ignore the condition
 Below are various kinds of conditional statement

1) If
2) If-Else
3) Else-If
4) Nested-If
5) Switch
6) Go-to

Sample program To perform Conditional statements

Action()
   {                            

   int a,b,c;
   a=rand()%21+31;
    lr_output_message("the value of a=%d,a");
    // lr_output_message is predefined fun prints the message on the screen
      If(a>40)   
    {
     lr_output_message("the value of a is greater 40");
    else if(a<40)
      lr_output_message("the value of a is less then 40");
    else if
     lr_output_message("the value of a is = 40");
       return 0;        //To release the allocated memory   

A Program To perform Conditional statements along with & operator 

Action()
{                            

int a,b,c;
a=rand()%81+10; //10-90
lr_output_message("The value of a=%d,a");
// lr_output_message is predefined fun prints the message on the screen
If(a<=25)   
{
lr_output_message("The value of a is Less then or equal to 25");
else if(a>25 && a<50)
lr_output_message("The value of a is in between 25 and 50");
else if(a>50 && a<75)
lr_output_message("The value of a is in between 50 and 75");
else if(a>50 && a<75)
lr_output_message("The value of a is in between 50 and 75");
else if(a>=75)
lr_output_message("The value of a  is greater then or equal to 75");
return 0;        //To release the allocated memory   

Loops:

Repeats a statement or group of statements when a given condition is true. First it will check whether the given condition is true then it will enters into loop other wise it will just comes out of the loop.

There are three kind of loops which are
1) For Loop
2) While Loop
3) Do-While Loop

For loop:
->In For loop initialization ,condition and iteration(Increment/Decrements) at one place.
->If we are not initializing the value then by default the value is '0'
->Iteration can be done inside the for loop as well

Syntax:

for(initialization ;condition;iteration(Increment/Decrements) )
{
Statement 1
Statement 2
-----------------
}

Sample program To perform For Loop

Action()
{                          

int a,
for(a=5;a<=10;a++)
{
lr_output_message("The value of a  =%d",a);
}
return 0;        //To release the allocated memory     

}

While loop:
->In While loop initialization ,condition and iteration(Increment/Decrements) can not placed in place.
->In While Loop It check the condition and execute the statement.


Syntax:

initialization ;
while(condition)
{
Statement 1
Statement 2
-----------------
iteration(Increment/Decrements);

}

Sample program To perform For Loop

Action()
{                          

int a=5,
while(a<=10)
{
lr_output_message("The value of a  =%d",a);
a++;
}
return 0;        //To release the allocated memory     

}

Do-While loop:
->In Do-While loop initialization ,condition and iteration(Increment/Decrements) can not placed in place.
->In Do-While Loop It will execute the statement first and later it will check the condition.


Syntax:

initialization ;
while(condition)
{
Statement 1
Statement 2
-----------------
iteration(Increment/Decrements);

}

Sample program To perform For Loop

Action()
{                          

int a=5,
do
{
lr_output_message("The value of a  =%d",a);
a++;
}while(a<=10);
return 0;        //To release the allocated memory     

}