There are errors in the function prototype and definition. The function prototype in line 4 declares the function as int fnAdd(int iValue1, int iValue2) but the definition in line 14 is int fnAdd(inum1, inum2). The parameter names must match between the prototype and definition.

1. UNIVERSITI TUN HUSSEIN ONN MALAYSIA
FACULTY OF MECHANICAL AND MANUFACTURING ENGINEERING
BTI 10202: COMPUTER PROGRAMMING
LAB 9 : Functions
NAME : _____________________________________
MATRICS NO.: _______________ DATE : ____________ MARK
Objective: Introduce to the usage of a function, types of function and function
Theory:
1. A function is a section of program that perform specific task. For an example; in real life, a
big project is split into sub project (e.g: contactor manage subcontract to finish a building).
The same method can be used to segregate certain task in programming.
a. Main function: to call sub function accordingly
b. Sub function one: to receive information and calculate
c. Sub function to : to display the result
2. Function definition: consist of two parts:
a. Function header: divided into three parts:
Prototypes declaration example:
Return_type function_name (parameters_list);
i. A return type
• Similar to variable type: int (round number), char (letter and
strings), float/double (decimal numbers), void (no returning value).
ii. A function name
• Use easy to understand sub function name that complies with the
syntax rules
iii. Parameter lists
• The list of data for communication purpose with the calling
functions. If there is no data to be use, the keyword void is use.
b. Function body normally contains:
i. Local declaration
ii. Local definition
iii. Return expression (this does not apply to function without any returning
value)
3. Function call is a postfix expression to call a sub functions/how to call function from any
functions:
Example:
printf(“The result is %d”, add(a,b)); //a function can be call from printf
display();//direct instruction to jump to the sub function
total=add(a,b); //assigning sub function add to total

2. Exercise 1: type the coding below and answer the following questions:
1 #include<stdio.h>
2 #include<conio.h>
3
4 int fnAdd(int iValue1, int iValue2);
5
6 int main() {
7 int iResult,iValue1=8, iValue2=9;
8
9 iResult = fnAdd(iValue1, iValue2);
10 printf("Sum of %d and %d is %dn",iValue1, iValue2, iResult);
11 getch();
12 return 0; }
13
14 int fnAdd(int iValue1, int iValue2)
15 {
16 int iSum;
17 iSum = iValue1 + iValue2;
18 return (iSum); }
i. What is the output of the coding? Output:
ii. Change line 4 with int fnAdd(int iNum1, int iNum2) ;
line 14 with int fnAdd(int iNum1, int iNum2) and
line 17 iSum = iNum1 + iNum2;
Compile and run the coding. Explain how this change affects the output. Output:
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iii. Revert to original coding. Remove coding in line 9
Change line 10 with printf("Sum of %d and %d is %dn",iValue1, iValue2,
fnAdd(iValue1, iValue2));
Compile and run the coding. Explain how this change affects the output. Output:
Explains what you learn:
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iv. Change line 7 with float iResult,iValue1=8, iValue2=9;

3. List the error and explains:
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v. Revert to original coding. Change line 14 with int fnAdd(inum1, inum2)
List the error and explains: