How to evaluate the string equation in ios

Question

Is there way to solve the string equations in ios ?

For example

Input:

NSString * str =@\"1+2\";

Output:

<

Answer 1

Use this :

NSString * str =@"1+2";

NSArray *arr = [str componentsSeparatedByString:@"+"];
int sum = 0;
for (int i = 0; i < [arr count]; i++) {
    sum += [[arr objectAtIndex:i] intValue];
}
NSLog(@"sum : %d",sum); 

Output : sum = 6

You can use NSExpression also.

Expressions are the core of the predicate implementation. When expressionValueWithObject: is called, the expression is evaluated, and a value returned which can then be handled by an operator. Expressions can be anything from constants to method invocations. Scalars should be wrapped in appropriate NSValue classes.

Example :

    NSLog(@"sum : %@", [[NSExpression expressionWithFormat:@"1+4"] expressionValueWithObject:nil context:nil]);
Output :- sum : 5
    NSLog(@"mulitple : %@", [[NSExpression expressionWithFormat:@"2*4"] expressionValueWithObject:nil context:nil]);
Output :- mulitple : 8

Hope it helps you.