1. Functions continued

2. Function comments
/** * Function: GetIntInRange * * Description: Asks the user for an integer in between the selected limits. * Repeats until requirements are met and returns the number. * Outputs a warning when input is out of range. * Parameters: min - integer, lower limit for the user input (inclusive) * max - integer, upper limit for the user input (inclusive) * Return: Integer number within the specified limits */
2018
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3. More about functions
Using global variables is often not recommended, also forbidden during this subject
When calling a function, only the variables, which has an important value at that time, should be passed
Arrays cannot be returned. However you can pass them.
Temporary variables, loop counters etc. should always be local
Only one value can be returned. To modify multiple single values, pointers are needed (by reference) – future topic
Similar blocks of code (copy-paste with minor differences) should be made into functions. Use variables to handle those differences.
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4. Where to declare?*
int SumArrayMembers(int numbers[], int arrLen) { int sum, i; sum = 0; for (i = 0; i < arrLen; i++) sum += numbers[i]; } return sum;
2018
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5. Where to declare?*
int main(void) { double avgBaddiesDisposed; char avengers[AVENGER_LIM][NAME_LIM]; int disposeCount[AVENGER_LIM]; int avengerCount = GetAvengerCount(LOWER_LIM, AVENGER_LIM); FillMissionStats(avengers, disposeCount, avengerCount); avgBaddiesDisposed = FindAvgBaddieDisposedOf(disposeCount, avengerCount); DisplaySlackers(avengers, disposeCount, avengerCount, avgBaddiesDisposed); return 0; }
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6. A few reminders and hints
Array length must always be passed!
At least (n – 1) array dimensions must be defined, however you can always fix all of them
To change the placement of two numbers, you need to swap them using 3 assignment statements
Initializing to zero:
int vector[LEN] = {0};
int matrix[ROWS][COLS] = {{0}};
2018
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7. A few reminders and hints
printf() vs putchar() vs puts()
printf() – print formatted – print formatted text, manual line changes
puts() – put string – print plain text, no format, automatic line change
putchar() – put character – prints one character
Character – between apostrophes e.g. ‘a’, ‘c’, ‘\n’, ‘\b’, ‘\0’
Character array (string) – between quotation marks e.g. "a", „hello"
2018
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8. The result of the lab task
Familiarize yourself with the finished program (given)
10_lab_switch_linux
Store it on the P drive
To run it, go to the location where You stored it using the terminal if „permission denied“ appears, chmod _lab_switch_linux
Run using it from the terminal
NB! The binary was compiled for the lab computers, might not work everywhere
10_lab_switch_windows.exe
Under Windows, You should be able to run this either from the command line or just by opening it up normally
Normally you should never run a binary file from an untrusted source
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9. Lab task (use basecode, mimic our program)
Generate a matrix (n*m) with random elements. Create limits if necessary.
n and m are entered by the user
Allow user to display the matrix
Only use while() loops
Allow user to generate a new matrix with new dimensions
Only use do while() loops
Task 2:
Allow user to switch 2 rows
Only use for() loop
Allow user to switch 2 columns
All operations must be repeatable without exiting the program
We’ve created a menu structure for you. You must create the code for each of the menu options
Actions must be performed inside of functions (call the from the menu)
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10. Advanced Allow the user to remove rows and/or columns
Allow the user to add rows and/or columns at the desired location
Allow the user to replace row, column or an element
Allow the user to mirror the matrix horizontally and vertically
Allow the user to transpose the matrix
Create the necessary menu structure and functions for the added functionality
2018
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