1. Modular Programming with Functions
B. Ramamurthy
Chapter 7
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2. Introduction Complex problems: Divide and conquer Reusability of code
Modular design of software to enhance readability and maintenance.
Abstraction
Information hiding
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3. Libraries of Functions
We have used functions from many libraries:
cmath : pow, sin, cos
fstream : open, close, get, set
iomanip: setw, setprecision
iostream : << , >>
Programmers can define functions for use in their program: programmer-defined functions.
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4. Functions Definition Function header Function parameters Function body
Function return value
In fact main() is a function.
int main() { …
return 0; }
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5. Function syntax type functioName (parameters) {
declare local variables/constants
statements }
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6. Example int factorial (int n) { int prod =1;
for (int i = 1; i <= n; i++)
prod = prod *i;
return prod; }
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7. Example: drawRectangle
*********
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8. Draw a small rectangle
***
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9. Draw a large rectangle
**********************
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10. drawRectangle(..) for (int i4 = 1; i4 <= length; i4++)
{ for (int k = 1; k<= offset; k++)
cout<< ' ';
for (int j = 1; j<= width; j++)
cout <<'*';
cout<< endl; }
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11. Function Parameters Write a function for rectangle code
Parameterize the function: add length and width as parameters to the function
Call/Invoke function with different parameters.
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12. Summary Functions provide basic construct to modularize you solution.
Practice writing functions.
Read Chapter 7.
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