i need to call a php program from another php program in middle and need to execute that php program
like calling PHPA from PHPB program.
after PHPA program execution completed and then PHPB program should resume its execution and need to complete its running

You can use functions to solve your purpose

function progA 
{
.
.
.

}

function progB 
{
.
.
   progA();
. 
}

You can include another script. If the script is on another server you can use cUrl.