Convert a string into an int

See the NSString Class Reference.

NSString *string = @"5";
int value = [string intValue];

How about

[@"7" intValue];

Additionally if you want an NSNumber you could do

NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter numberFromString:@"7"];

I use:

NSInteger stringToInt(NSString *string) {
    return [string integerValue];
}

And vice versa:

NSString* intToString(NSInteger integer) {
    return [NSString stringWithFormat:@"%d", integer];
}

This is the simple solution for converting string to int

NSString *strNum = @"10";
int num = [strNum intValue];

but when you are getting value from the textfield then,

int num = [txtField.text intValue];

where txtField is an outlet of UITextField