怎么把c语言字符串转成oc字符串

如何把c语言字符串转成oc字符串

NSString *str = [[NSString alloc] initWithUTF8String: "123456"];[str release];

//不用释放内存NSString *str = [NSString stringWithFormat:@"i has %i and %.2f", 19, 1.223f];