Simplest for loop in C language example

A simple for loop explained in the following program written in C language.

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C programming language : for loop explained

Source Code :

#include
int main()
{
    int i;
    for(i=1;i<5;i++)
    {  
                 printf("i=%d\n",i);
    }
}

The first statement #include is a header file required to use the library functions in C. If you don’t understand this at this level then just think you need to write this line to learn a C program.

int main() is the main function body, you need to write it in most C programs. In the main function body i variable is declared by the statement int i. The main function is like the following :

int main()
{
}

In the for loop there is 3 parts :

for(initialisation ; checking a condition** ; increment or decremment)

{
For loop body;
}

**Condition is checked to determine – when the loop will end, otherwise a loop will run forever. There must be a decisive factor to end the loop otherwise the loop will run indefinitely and shall not stop. So always be careful about this. You need to terminate a loop after some time.

In the above example variable i is initialized with value 1. Then i < 5 condition is checked, so initially i=1 and it is less than 5 so the printf statement executes and value of i is printed.
Output: i=1

After that i is incremented by 1 by the statement i++, and then i becomes 2 and again i will be checked whether i < 5 or not ? Now i=2 and i<5 so the output will be

Output:
i=1
i=2

Again i is incremented by 1 by the statement i++, and then i becomes 3 and again i will be checked whether i < 5 or not ? Now i=3 and i<5 so the output will be

Output:
i=1
i=2
i=3

Again i is incremented by 1 by the statement i++, and then i becomes 4 and the output will be :
i=1
i=2
i=3
i=4

The Loop Terminates Now : Again i is incremented by 1 by the statement i++, and then i becomes 5 and again i< 5 condition is checked , but 5 is not less than 5, so i<5 becomes false and loop terminates and the program ends.

A video tutorial in YouTube on C For Loop:

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