Infinite loop in C
Definition of infinite loop
The infinite loop is a loop that does not get dismissed because of its looping construct. A continuous output or no output are the two possible outcomes of this loop. It is also known as an endless loop or an indefinite loop.
There are a lot of applications where an infinite loop is helpful in running applications continuously. Those applications also produce endless outputs until the process is terminated manually. A few of them are the following:
- Games: The user can play unlimited matches continuously, but if the user wants to stop the match, the h/.she has to exit the game manually. The game does not terminate on its own.
- Operating Systems: As we usually observe, any operating system does not terminate its functioning on its own after the completion of the task until and unless the user manually shuts down the system.
- Servers and website: Infinite loop is also used in servers and websites, which produce the continuous output as the user asks to carry out the process. This processing only gets dismissed when the user closes the website or when the administrator manually shuts the servers and websites down.
Now we will see how to initiate the infinite loop in various looping codes:
For loop
The statement for the infinite for loop is mentioned in the following block:
for(; ;) // initiating "Infinite For Loop".
{
// main body of the "Infinite For Loop".
}
In the above program line, no condition is mentioned so that it can produce infinite outcomes.
Now, it’s time to know precisely about this with the help of an example.
#include <stdio.h> // basic program line
int main()
{
// initialising without any condition
for(;;)
{
printf("Hello, world!!!\t"); // main program line
}
return 0;
}
Output:
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
Hello, world!!! Hello, world!!! Hello, world!!! Hello, world!!!
While loop
// here, 1 represents the condition as true
while(1)
{
// main body of the "infinite while loop".
}
Example of Infinite while loop:
// basic program lines
#include <stdio.h>
int main()
{
int a=1; // initialising the value of a as 1
while(1)
{
a++; // increment or decrement statement
printf("now a is:%d \t",a);
}
return 0;
}
Output:
188 now a is:125189 now a is:125190 now a is:125191 now a is:125192 now a is:125193 now a is:125194 now a is:125195 now a is:125196 now a is:125197 now a is:125198 now a is:125199 now a is:125200 now a is:125201 now a is:125202 now a is:125203 now a is:125204 now a is:125205 now a is:125206 now a is:125207 now a is:125208 now a is:125209 now a is:125210 now a is:125211 now a is:125212 now a is:125213 now a is:125214 now a is:125215 now a is:125216 now a is:125217 now a is :Do-while loop
do
{
// main body of the infinite do-while loop.
}
while(1);
Example of Infinite Do-while loop:
#include <stdio.h> // basic program line
int main()
{
do
{
printf("Hello !!"); // main body of the infinite do while loop..
}
while(1); // 1 is considered as true and 0 as false
}
Output:
Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello!!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello !!Hello