NsString Length Pleeease Help

Question

Hi,

I want to get my stringvalue length -1 in Objective -C ,But I couldnt I share my code below please help me....

double operand;
double waitingOperand;
NString *waitingOperation; 
NString *forCharString; 
NString *forCharRanges; 
NSMutableString * lengthString;


forCharString = [NSString stringWithFormat:@"%f", operand];
lengthString = [NSString stringWithFormat:@"%d",forCharString.length];
forCharRanges = [forCharString substringWithRange:NSMakeRange(0,[lengthString intValue])];
operand = [forCharRanges doubleValue];

Thank You