Data Types and Operators in C Programming

Data Types and Operators in C Programming

• 1.
  C PROGRAMMING LECTURE 17th August IIT Kanpur CCourse, Programming club, Fall 2008 1
• 2.
  Recap C Course, Programmingclub, Fall 2008 2  C is a high-level language.  Writing a C code. {editors like gedit, vi}  Compiling a C code. {gcc –c test.c –o test}  Executing the object code. {./test}
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  Some more basics CCourse, Programming club, Fall 2008 3  Keywords  char, static, if , while, return ..................... Total= about 32  Data Types  int , char, float ...………..….. Some more later  Arithmetic Operators  + (Plus), - (Minus), * (Multiplication), /(Division) ……….………. Some more later
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  My first Cprogram! C Course, Programming club, Fall 2008 4 #include <stdio.h> // program prints hello world int main() { printf ("Hello world!"); return 0; } Output: Hello world!
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  Example 1 C Course,Programming club, Fall 2008 5 #include <stdio.h> // program prints a number of type int int main() { int number = 4; printf (“Number is %d”, number); return 0; } Output: Number is 4
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  Example 2 C Course,Programming club, Fall 2008 6 #include <stdio.h> // program reads and prints the same thing int main() { int number ; printf (“ Enter a Number: ”); scanf (“%d”, &number); printf (“Number is %dn”, number); return 0; } Output : Enter a number: 4 Number is 4
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  more and more CCourse, Programming club, Fall 2008 7 #include <stdio.h> int main() { /* this program adds two numbers */ int a = 4; //first number int b = 5; //second number int answer = 0; //result answer = a + b; }
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  Note C Course, Programmingclub, Fall 2008 8 Errors Compilation Compiler generally gives the line number at which the error is present. Run time C programs are sequential making the debugging easier.
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  Some more DataTypes C Course, Programming club, Fall 2008 9  Primary : int, float, char  int (signed/unsigned)(2,4Bytes): used to store integers.  char (signed/unsigned)(1Byte): used to store characters  float, double(4,8Bytes): used to store a decimal number.  User Defined:  typedef: used to rename a data type  typedef int integer; can use integer to declare an int.  enum, struct, union
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  Some more ArithmeticOperators C Course, Programming club, Fall 2008 10  Prefix Increment : ++a  example:  int a=5;  b=++a; // value of b=6; a=6;  Postfix Increment: a++  example  int a=5;  b=a++; //value of b=5; a=6;
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  Contd… C Course, Programmingclub, Fall 2008 11  Modulus (remainder): %  example:  12%5 = 2;  Assignment by addition: +=  example:  int a=4;  a+=1; //(means a=a+1) value of a becomes 5 Can use -, /, *, % also
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  Contd… C Course, Programmingclub, Fall 2008 12  Comparision Operators: <, > , <=, >= , !=, ==, !, &&, || .  example:  int a=4, b=5;  a<b returns a true(non zero number) value.  Bitwise Operators: <<, >>, ~, &, | ,^ .  example  int a=8;  a= a>>1; // value of a becomes 4
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  Operator Precedence C Course,Programming club, Fall 2008 13  Meaning of a + b * c ? is it a+(b*c) or (a+b)*c ?  All operators have precedence over each other  *, / have more precedence over +, - .  If both *, / are used, associativity comes into picture. (more on this later)  example :  5+4*3 = 5+12= 17.
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  Precedence Table C Course,Programming club, Fall 2008 14 Highest on top ++ -- (Postfix) ++ -- (Prefix) * / % + - << >> < > & | && ||
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  Input / Output CCourse, Programming club, Fall 2008 15  printf (); //used to print to console(screen)  scanf (); //used to take an input from console(user).  example: printf(“%c”, ’a’); scanf(“%d”, &a);  More format specifiers %c The character format specifier. %d The integer format specifier. %i The integer format specifier (same as %d). %f The floating-point format specifier. %o The unsigned octal format specifier. %s The string format specifier. %u The unsigned integer format specifier. %x The unsigned hexadecimal format specifier. %% Outputs a percent sign.
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  Some more geekstuff C Course, Programming club, Fall 2008 16  & in scanf.  It is used to access the address of the variable used.  example:  scanf(%d,&a);  we are reading into the address of a.  Data Hierarchy.  example:  int value can be assigned to float not vice-versa.  Type casting.
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  Home Work C Course,Programming club, Fall 2008 17  Meaning of  Syntax  Semantics of a programming language  Find the Output:  value=value++ + value++;  Value=++value + ++value;  value=value++ + ++value;
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  End of Today’sLecture C Course, Programming club, Fall 2008 18 Doubts && Queries?
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  THANK YOU C Course,Programming club, Fall 2008 19