Functions in c

  • What is a Function?

    • A function in C is a block of code that performs a specific task. It can take inputs, process them, and produce outputs. Functions provide a way to organize code into manageable pieces, promote reusability, and enhance the readability of programs.

  • Syntax of a Function :

    • A function in C follows a basic syntax :
    return_type function_name(parameters) {
      // function body
    }
    return_type : The type of value the function returns to the calling code. It can be 'void' if the function doesn't return anything.
    function_name : The name of the function, which is used to call it from other parts of the program.
    parameters : Any values passed to the function for processing. These are optional.
    function body : The block of code that defines what the function does.

  • Function Calls :

    • To use a function, you simply call it by its name, passing any required arguments inside parentheses. For example : Calling the add function with arguments 3 and 4
    int result = add(3, 4);

  • Return Statement :

    • Functions may return a value using the 'return' statement. It exits the function and passes a value (if required) back to the caller.
    return a + b;

  • Void Functions :

    • Functions that don't return any value are termed as 'void' functions. They are declared and defined with void as the return type.
    void sayHello() {
      printf("Hello, PBA INSTITUTE!");
    }

  • Examples :
    • C Code
    #include <stdio.h> int add(int a, int b) { return a+b; } main() { int result = add(3,4); printf("Add=%d", result); }

    Output :
    Add=7
    In this example :
    - 'add' is the name of the function.
    - 'int' before the function name specifies the return type of the function. In this case, the function returns an integer.
    - 'int a' and 'int b' are the parameters passed to the function.
    - Inside the function body, 'a' and 'b are added together, and the result is returned using the return statement.
    - In the main function, 'add(3, 4)'' is called, and the result is stored in the result variable.
    - Finally, the 'printf' function is used to print the sum.

    C Code
    # Write a program to accept a number and check whether number is Even or odd, using the function name void check (int n). #include<stdio.h> void check(int n) { int t,r,s; if(n%2==0) printf("Even"); else printf("Odd"); } main() { int n,t; printf("Enter a number="); scanf("%d",&n); check(n); }

    Output :
    Enter a number=4
    Even

    C Code
    # Write a program to find the sum of any ten natural numbers, using the function name sum (int n). #include<stdio.h> void sum(int n) { int s=0,i; for(i=1;i<=n;i++) { s=s+i; } printf("sum=%d",s); } main() { sum(10); }

    Output :
    sum=55

    C Code
    # Write a program to print the last digit of given number , using the function lastdigit(). #include<stdio.h> void lastdigit(int n) { int i; i=n%10; printf("last digit is=%d",i); } main() { int n,i; printf("enter a number="); scanf("%d",&n); lastdigit(n); }

    Output :
    enter a number=123
    last digit is=3

  • Conclusion :

    • Functions are fundamental building blocks in C programming, offering modularity, reusability, abstraction, maintainability, scalability, readability, performance optimization, encapsulation, and information hiding. Mastering the use of functions is essential for writing efficient, robust, and maintainable C programs.

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