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 string