c语言常见笔试题总结

1、【1 使用宏】1.1#ifdef NDEBUG#define TRACE(S S#else#define TRACE(S printf(“%s;n”, #S; S#endif问:以上TRACE(宏的作用是什么?1.2 #error的作用?1.3 定义一个宏,求出给定数组中的元素的个数#define NELEMENTS(array ?1.4 定义一个宏,求出给定结构中给定成员的偏移量#define OFFSET(structure, member ?【2 数据声明和定义】给定以下类型的变量a的定义式:a An integerb A pointer to an integerc A pointer

2、 to a pointer to an integerd An array of 10 integerse An array of 10 pointers to integersf A pointer to an array of 10 integersg A pointer to a function that takes an integer as an argument and returns an integerh An array of ten pointers to function s that take an integer argument and return an int

3、eger 【3 复杂类型(1】有如下表达式:char (*(*x(;请用文字描述x是什么。【4 复杂类型(2】jmp_buf的定义:typedef struct _jmp_bufREG_SET reg;int extra3; jmp_buf1;setjmp函数的原型:extern int setjmp (jmp_buf _env;问:调用setjmp时传递_env的内容,还是传递指针?【5 头文件】问:为什么标准头文件都有类似以下的结构?#ifndef _INCvxWorksh#define _INCvxWorksh#ifdef _cplusplusextern “C” #endif/*/#i

4、fdef _cplusplus#endif#endif /* _INCvxWorksh */【6 static关键字】请说出static关键字的3种用处:(1用于全局变量;(2用于局部变量;(3用于函数。/* file.c */static int a;int b;static int fn(static int x;int y;【7 const关键字】7.1 const关键字的意义是什么?7.2 解释以下的变量定义:const int a1;int const a2;const int *a3;int * const a4;int const * const a5;【8 volatile关键

5、字】8.1 volatile意义?例如volatile int *p;8.2 volatile能和const一起使用吗?例如volatile const int *p;【9 sizeof(】有以下定义:char *pmsg = “A”;char msg = “A”;char ch = A;问:sizeof(pmsg = ?sizeof(msg = ?sizeof(“A” = ?sizeof(ch = ?sizeof(A = ? (在C+中等于多少? void f(char param100/ sizeof(param = ?【10 字符串】有以下代码char *pmsg = “hello, world!”;strcpy(pmsg, “hi, there.”;试评论该代码。【11 混合运算】有以下代码:void foo(unsigned int a = 6;int b = -20;(a+b > 6 ? puts(“> 6 : puts(” < = 6; 请问调用foo(的输出?【12 内存访问】有以下代码:void fn(int a100;int *p;p = (int *(unsigned inta + 1;printf(“p=0x%xn”, *p;试评论以上代码。【13 C库函数】请说明以下函数的意义:v