sri ramanuja seva

Questions and Answers, for CS 3251 – Programming in C. Part 6.
(For Part 5 of this series, pls see here: 16 marks Q & A on Loops (Unit 1). )

Pls see the above images. The same content is given in text form below.

Anna Univ Exam Prep: CS 3251: Programming in C: Previous Years Questions and Answers – Part 5.
In this post, Q&A related to Functions (Unit 3).

Question (Nov / Dec 2022) (16 marks)

(a) Classify function prototypes with suitable examples. (8 marks)

(b) Write a program to design scientific calculator using built-in functions. (8 marks)

Note: Part (a) of this question is answered in this post. Part (b) will be answered in a subsequent post.

Answer (a) Classification of function prototypes, with examples.

• Function prototype is also known as function declaration.
• It is written prior to the function call and the function definition.
• It conveys the following information to the compiler:
  • Function name
  • Return type
  • Number of parameters and types of parameters

Based on return value and parameters/arguments, function prototypes are of 4 types:

• Functions with no parameters and no return value.
• Functions with one or more parameters, and no return value.
• Functions with no parameters, and returning a value.
• Functions with one or more parameters, and returning a value.

1. Function with no parameters, and no return value

• Calling function does not pass any arguments.
• Function does not return any value to the calling function.

#include <stdio.h>
void greet(void);    // function prototype
int main()
{
    greet();         // function call
    return 0;
}
void greet(void)     // function definition
{
    printf("Have a nice day.\n");
}

output: 
Have a nice day. 

2. Function with one or more parameters, and no return value

• Calling function passes one or more parameters (arguments).
• Function does not return any value to the calling function.

#include <stdio.h>
void Add(int, int);    // function prototype
int main()
{
    Add(10, 20);       // function call
    return 0;
}
void Add(int m, int n)    // function definition
{
    printf("Sum of %d and %d is %d", m, n, m + n);
}

output: 
Sum of 10 and 20 is 30 

3. Function with no parameters, and returning a value

• Calling function does not pass any parameters (arguments).
• Function returns a value to the calling function.

#include <stdio.h>
int getCurrentYear(void);    // function prototype
int main()
{
    printf("Current year is %d", getCurrentYear());    // function call
    return 0;
}
int getCurrentYear(void)    // function definition
{
    return 2026;
}

output: 
Current year is 2026

4. Function with one or more parameters, and returning a value

• Calling function passes one or more parameters (arguments).
• Function returns a value to the calling function.

#include <stdio.h>
int Add(int, int);    // function prototype
int main()
{
    printf("Sum of %d and %d is %d", 10, 20, Add(10, 20));    // function call
    return 0;
}
int Add(int m, int n)    // function definition
{
    return m + n;
}

output: 
Sum of 10 and 20 is 30 

To write a good answer for this question, do these things –

• Explain briefly what a function prototype is.
• Mention the 4 types of function prototypes.
• Write simple code examples for each type.
  • When writing code, add comments to indicate which is function prototype, which is function call, and which is function definition.
• write neatly and legibly.