A simple C program: Printing a line of text

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A simple C program Printing a line of text

• include ltstdio.hgt
• main()
• printf(hello, world\n)
• Program output
• hello, world

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More C programs

• include ltstdio.hgt
• main()
• printf(My first program.\n)
• printf(It is wonderful.)
• Program output
• My first program.
• It is wonderful.

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More C programs

• include ltstdio.hgt
• main()
• printf(My first program.)
• printf(It is wonderful.)
• Program output
• My first program.It is wonderful.

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Printing characters

• Source program
• printf(Welcome\nto\nCOMP 1180!\n)
• Program output
• Welcome
• to
• COMP 1180!
• You can use printf to print a string of
  characters
• but there are special cases
• For double quote, use \
• For single quote, use \
• For backslash, use \\
• For newline, use \n

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Formatted Output (integer,float,char,string)

• Almost every C program start with the following
• include ltstdio.hgt
• for the access to the standard input/output
  library
• For the printf statement
• printf(format-string, arg1, arg2, ...)
• Format-string tells the program how to print the
  arguments out
• Format-string contains two types of objects
  ordinary characters and conversion specifications
• Each conversion specification begins with a and
  ends with a conversion character and maybe have a
  minus sign, a number, and a period in between

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Basic Printf Conversions

• d i integer
• o octal (Base 8)
• x X hexadecimal (Base 16)
• f floating point
• e E floating point (exponent)
• g G floating point (general format)
• c single character
• s character string
• print a

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Examples on Formatted Printf Statements

• int a 5 int b 10 123456789012345
• printf(d\n, a) 5
• printf(5d\n, a) 5
• printf(5d\n, b) 10
• printf(d d\n, a, b) 5 10
• printf(a d b 3d\n, a, b) a 5 b
  10
• float x 33.3456789 123456789012345
• printf(f\n, x) 33.345679
• printf(e\n, x) 3.33457e01
• printf(8.3f\n, x) 33.346
• x 0.3334567
• printf(e\n, x) 3.33457e-01

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More Examples on Printf (strings)

• printf(s, hello, world) hello, world
• printf(10s, hello, world) hello, world
• printf(.10s, hello, world) hello, wor
• printf(-10s, hello, world) hello, world
• printf(.15s, hello, world) hello, world
• printf(-15s, hello, world) hello, world
• printf(15.10s, hello, world) hello,
  wor
• printf(-15.10s, hello, world) hello, wor
  

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Formatted Input

• For scanf statements,
• scanf(format-string, addr1, addr2, ...)
• Examples
• float f
• int lower, upper
• char ch
• scanf(f, fahr)
• scanf(dd, lower, upper)
• scanf(c, ch)
• ch getchar() get the next character from
  STDIN
• putchar(ch) put the character to STDOUT