Objective-C 强制类型转换

NSString *str = @"1";
    // 字符转int
    int intV = [str intValue];
    // int转字符
    NSString *stringInt = [NSString stringWithFormat:@"%d", intV];
    // 字符转float
    float floatString = [str floatValue];
    // float转字符
    NSString *stringFloat = [NSString stringWithFormat:@"%f", floatString];