GIDACalculateString

Class to parse an input string and calculate its value. The string can contain numbers, ., (, ), /, *, -, and + symbols. It also checks, that if the user adds a number, ., (, ), /, *, -, or + to a string, would that string be a valid string to calculate or not.

Tasks

Verification

+(BOOL)usingThis:(NSString *)string addThis:(NSString *)newString;
+(BOOL)usingThis:(NSString *)string addThis:(NSString *)newString here:(NSRange)range;

Creation

+(NSString *)stringFrom:(NSString *)string withThis:(NSString *)newString;
+(NSString *)stringFrom:(NSString *)string withThis:(NSString *)newString here:(NSRange)range;

Solver

+(NSNumber *)solveString:(NSString *)string;

Properties

usingThis:addThis:

Check if adding a new string, at the end, to a previous string would create a valid expression.

+(BOOL)usingThis:(NSString *)string addThis:(NSString *)newString;

Parameters
string
Base string where you want to add.

newString
String to check if adding it would create a correct expression.

Return Value
YES if adding the newString to string would create a valid expression, otherwise NO

Discussion
This assumes the newString would be added at the end of string.

usingThis:addThis:here

Check if adding a new string, at the specified location, to a previous string would create a valid expression.

+(BOOL)usingThis:(NSString *)string addThis:(NSString *)newString here:(NSRange)range;

Parameters
string
Base string where you want to add something.

newString
String to check if adding it would create a correct expression.

range
Range where string would be added.

Return Value
YES if adding the newString to string would create a valid expression, otherwise NO

stringFrom:withThis:

+(NSString *)stringFrom:(NSString *)string withThis:(NSString *)newString; Add a new string to the end of a previous string.

Parameters string
Base string where you want to add.

newString
String to check if adding it would create a correct expression.

Return Value
A string with containing the previous string with the new string appended.

stringFrom:withThis:here:

Add a new string at the specified location to a previous string.

+(NSString *)stringFrom:(NSString *)string withThis:(NSString *)newString here:(NSRange)range;

Parameters
string
Base string where you want to add something.

newString
String to check if adding it would create a correct expression.

range
Range where string would be added.

Return Value
A string with containing the previous string with the new string in the specified location.

solveString:

Solve an mathematical expression.

+(NSNumber *)solveString:(NSString *)string;

Parameters
string
String containing the mathematical expression.

Return Value
A number with the result of the mathematical expression, nil if it is not a well formed expression.