IT Lesson

Functions in C Programming

#include<stdio.h>

void firstfu();
void secondfu();
void thirdfu();
void fourthfu();


void main()
{
 printf(" Control is in main
");
 firstfu();
}

void firstfu()
{
 printf(" Now the control is in firstfu function
");
 thirdfu();
}

void secondfu()
{
 printf(" Now the control is in secondfu function
");
 fourthfu();
}

void thirdfu()
{
 printf(" Now the control is in thirdfu function 
");
 secondfu();
}

void fourthfu()
{
 printf(" Now the control is in fourthfu function 
");
}

• The program starts with main() function and it will print the message inside it. After that I have called the firstfu() function from main(). Remember here main() is calling function and firstfu() is called function.
• Now the control reaches to firstfu() function and the activity of main() function is suspended temporarily. Inside firstfu() function, printf() will print a message. Now I have called thirdfu() function. Remember here firstfu() is calling function and thirdfu() is called function
• Now the control reaches to the thirdfu() function and the activity of firstfu() function is suspended temporarily. And it will execute its printf() function. Now I have called the secondfu() function.
• Same thing will happened to the secondfu() function and it will call the fourthfu() function.
• Now the printf() statement will be executed inside the fourthfu() function. As there is no further call to other function there. So the control will goes back to the calling function. Calling function of fourthfu() is secondfu().
• No more statements is left in secondfu(). So the control will reach to the calling function. thirdfu() is the calling function of secondf().
• Same execution will be done for all of them. And the control will reach to the main() function again. Now no statement is left in main() function, so the program will be terminated.