String Manipulation

RobotC provide native support for string variables. This is an extension beyond the normal capabilities found in the ‘C’ language; in standard ‘C’ strings are manipulated with arrays of ‘;char’.

String variables can contain up to 20 characters;  20 characters was chosen because it is more characters than will fit on one line of the NXT display.

Native support means that normal “opcodes” apply to strings. In particular, you can:

• Declare a string variable

string stringA;                 // Define a string variable

string stringB = “Hello World;  // Define a string variable with an initial value

string stringD[10];             // Define a string array of 10 elements.

• Use the assignment operator (‘=’) with strings.

stringA = stringB;

stringA = “Hello World”;

• Use the concatenate operator (‘+’) with strings.

stringA  = stringB + stringC;  // stringA           is the concatenated result of ‘stringb’ with ‘stringB’

stringA += stringB;            // stringA           is added to the end of stringA

stringA += “More Characters”;  // “More Characters” is added to the end of stringA

• Use the comparison operators in string expressions

if (stringA == stringB) . . .

if (stringA >= stringB) . . .

if (stringA <  stringB) . . .

etc

The following functions also apply to string variables.

StringDelete(sDest, nIndex, nSize);

Deletes a substring from a string

StringFind(sDest, nIndex, sSearch);

Finds the position in a string of the selected substring

StringFormat(sDest, sFmtSpec, nParm1, nParm2);

Formats a string using the specified format string and up to two parameters for formating

strLen(sString)

Functions returns the size of a string