Mastering C Programming: printf, scanf, and Variable Swapping Techniques

1. C Programming

2. printf • intprintf ( const char * format, ... ); • printf ("Characters: %c \n", 'a'); • printf ("Decimals: %d %f\n", 1977, 3.14);

3. Printf - float • %f – floating point. Displays upto 6 decimal places. • %0.2f- displays 2 decimal places • %5.1f- displays 4 digits including one after decimal point. If less digits are there then it gives spaces instead • %05.1f- displays 4 digits including one after decimal point. If less digits are there then it gives leading zeros.

4. Printf – decimal • %5d- displays a the value. If number of digits is less than 5 then leading spaces are given. • %-5d- here trailing spaces are given. • %05d- here instead of spaces zeros are given.

5. Scanf • Reads data from standard input and stores them according to the parameter format into the locations pointed by the additional arguments. • Eg: -inti; scanf ("%d",&i);

6. Coding standards • Variable • Each variable must strictly be named in a meaningful way • only one declaration of one variable in one line • Eg: -inttotal_marks; inttotalmarks; • File Name • Filenames should be all lowercase and can include underscores (_) or dashes • Eg:- helloworld.c or hello_world.c

7. Coding standards • Comments • Meaningful comments and should be proper sentences • No spelling mistakes in comments • Indenting • Two spaces should be used. • Line length • Max 80 characters per line

8. Question 1 • Swap two variables using a temporary variable. • Input • Enter integer value 1- 10 • Enter integer value 2- 20 • Output • Value 1= 10 • Value 2= 20 • After Swapping • Value 1= 20 • Value 2= 10

9. Question 2 • Compute volume of a cylinder • Input • Enter the radius of cylinder (float) • Enter height of cylinder in float • Output • Volume of the cylinder(round off to 2 decimal places) =