Variable initialization and assignment

Transcription

1 Variable initialization and assignment int variable_name; float variable_name; double variable_name; String variable_name; boolean variable_name; Initialize integer variable Initialize floating point variable Intialize double precision floating point variable Initialize String variable Initialize boolean variable int variable_name = expression; Initialize integer variable with given value float variable_name = expression; Initialize floating point variable with given value double variable_name = expression; Intialize double precision floating point variable with given value String variable_name = string expression; boolean variable = boolean expression; Initialize string variable with given string; Initialize boolean variable with given boolean expression variable = expression; Assign a new value for variable

2 Operators + Calculate the sum of numeric variables or concatenate strings - Calculate the difference of numeric variables * Calculate the product of numeric variables / Calculate the quotient of numeric variables % Calculate the modulus of numeric variables ++ Increase the value of integer type variable with one -- Decrease the value of integer type variable with one += Increase the value of numeric variable with given expression -= Decrease the value of numeric variable with given expression *= Multiply a numeric variable with given expression /= Divide a numeric variable with given expression Relational operators var1 == var2 var1!= var2 var1 < var2 var1 > var2 var1 <= var2 var1 >= var2 Returns true, if var1 is equal to var2 Returns true, if var1 is not equal to var2 Return true, if var1 is less than var2 Return true, if var1 is greater than var2 Returns true if var1 is equal or less than var2 Returns true if var1 is equal or greater than var2

3 Conditional statements if (expression){ if (expression){ 1 else{ 2 if (expression1){ 1 else if (expression2){ 2 Execute if expression equals true Execute 1 if expression equals true, otherwise execute 2 Execute 1 if expression1 equals true; execute 2 if expression1 equals false and expression2 equals true Loop statements while (condition){ do{ while (condition); for (var1 = var2; exit-condition; incrementor){ ; break; continue; Execute while the condition equals true Execute until the condition equals false Execute a a fixed number of times. Supported exit-conditions: var1 < var2 var1 > var2 var1 <= var2 var1 >= var2 Supported incrementors: var1++ var1 var1 = var1 + expression var1 = var1 expression Exit current loop Continue the execution from the start of the current loop

4 Method declarations public static void main(string[] args){ public static void method_name(parameter definitions) public static type private static void public void public type private void private type Declare a main method; mandatory in every ViLLE example Declare a public static procedure Declare a public static function of type type Declare a private static function of type type Declare a public procedure Declare a public function of type type Declare a private procedure Declare a private function of type type Tables type variable_name[] = new type[size]; type variable_name[][] = new type[size1][size2]; type variable_name[] = {value1, value2,,value_n; Declare a new table of size size and type type (int / float / double / boolean / String) Declare a new matrix of size1 x size2 and type type Declare a new table of type type and initialize it with value1 value_n. type variable_name[][] = {{a1,a2 vn,{b1,b2,,bn,,{z1,z2,,zn; table_var1 = table_var2; table_var.length Declare a new matrix of type type and initialize it with values a1 an, b1 bn,,z1 zn Change reference Return the size of the table

5 Output System.out.print(string); System.out.println(string); Output string Output string and move to next line String handling string.indexof(str1) string.substring(index) string.substring(index1,index2) string.indexof(string2) string.charat(index) string1.equals(string2) string.replace(string1,string2) string.length() Return the index of str1 in string Return the substring starting from index Return the substring starting from index1 and ending in index2 Returns the first index of string2 in string Returns the character at index Returns true, if string2 represents the same sequence of characters than string1 Return a new string with all occurrences of string1 replaced with string2 Return the length of string