What are function calls in C?

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What are function calls in C?

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For this you need to understand functions first

Functions are basically a set of instructions which are clumped together with a certain name given to them

This helps in preventing code from getting too repetitive. Say you have to do a certain calculation 5 times in your program. You could write all the code for the calculation every single time, but that would be very very repetitive. And what if you want to change how that calculation works now? You’ll have to go to all those places in your program and change the code there, again and again

Function calls are lines of code which run the function. C provides you some functions already (such as printf, scanf etc) (which are included in what’s called a standard library), or you can also make your own functions.

A function in a programming language is a set of instructions that you assign a name to, which allows you to use it in multiple places without retyping it. It also allows you to alter the input so the function becomes more versatile.

A function call is using that function in the main program.

For instance:

int sum(int x, int y) {

return(x + y);

}

Sum is a function which adds two inputs together.

You could then use this in the main function, which is automatically run when you start a C program.

int main(){

int a = 1, b = 2, c = 3, ans1, ans2;

ans1 = sum(a,b);

ans2 = sum(b,c);

…..

}

If you were to run that program, and display ans1 and ans2, you would get ans1=3 and ans2=5. The function remains the same, but the input is different, so the answer is different.

Think of a function as a formula. The inputs are variables. And a function call solves the formula for the variables given. You can do this to improve code readability, prevent repetitive code, reduce file size, and set up event based functions (e.g. when the user clicks this button, run this function).

Function calls in any programming language is the identical concept to a function call you learned in math class. You should be familiar with the trigonometric sin() function. Using it in an expression x = sin(42) is the same on a math test as in code. You can define your own functions such as foo(x) = x+1 as a reusable expression for use elsewhere in your maths. In programming, it is more common to see piecewise functions or functions containing multiple statements. The function definition syntax between maths and code is different but has a lot in common.