C语言进阶课程学习记录- 函数与宏分析

news/2024/9/24 13:15:38/

C语言进阶课程学习记录- 函数与宏分析

- 实验-宏和函数
- 实验-宏的副作用
- 实验-宏的妙用
- 小结

本文学习自狄泰软件学院唐佐林老师的 C语言进阶课程，图片全部来源于课程PPT，仅用于个人学习记录

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实验-宏和函数

#include <stdio.h>#define RESET(p, len)          \while( len > 0 )           \((char*)p)[--len] = 0void reset(void* p, int len)
{while( len > 0 )((char*)p)[--len] = 0;
}int main()
{int array[] = {1, 2, 3, 4, 5};int len = sizeof(array);int i = 0;for(i=0; i<5; i++){printf("array[%d] = %d\n", i, array[i]);}//reset(array, len);//case1RESET(array, len);//case2for(i=0; i<5; i++){printf("array[%d] = %d\n", i, array[i]);}return 0;
}/*output:
array[0] = 1
array[1] = 2
array[2] = 3
array[3] = 4
array[4] = 5
array[0] = 0
array[1] = 0
array[2] = 0
array[3] = 0
array[4] = 0*/

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实验-宏的副作用

#include <stdio.h>#define _ADD_(a, b) a + b
#define _MUL_(a, b) a * b
#define _MIN_(a, b) ((a) < (b) ? (a) : (b))int main()
{int i = 1;int j = 10;printf("%d\n", _MUL_(_ADD_(1, 2), _ADD_(3, 4)));printf("%d\n", _MIN_(i++, j));//printf("%d\n", 1 + 2 * 3 + 4);//printf("%d\n", ((i++) < (j) ? (i++) : (j)));return 0;
}/*output:
11
2*/

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实验-宏的妙用

#include <stdio.h>
#include <malloc.h>#define MALLOC(type, x)   (type*)malloc(sizeof(type)*x)
#define FREE(p)           (free(p), p=NULL)#define LOG_INT(i)        printf("%s = %d\n", #i, i)
#define LOG_CHAR(c)       printf("%s = %c\n", #c, c)
#define LOG_FLOAT(f)      printf("%s = %f\n", #f, f)
#define LOG_POINTER(p)    printf("%s = %p\n", #p, p)
#define LOG_STRING(s)     printf("%s = %s\n", #s, s)#define FOREACH(i, n)     while(1) { int i = 0, l = n; for(i=0; i < l; i++)
#define BEGIN             {
#define END               } break; }int main()
{int* pi = MALLOC(int, 5);char* str = "D.T.Software";LOG_STRING(str);LOG_POINTER(pi);FOREACH(k, 5)BEGINpi[k] = k + 1;ENDFOREACH(n, 5)BEGINint value = pi[n];LOG_INT(value);ENDFREE(pi);LOG_POINTER(pi);return 0;
}/*output:
str = D.T.Software
pi = 00702D28
value = 1
value = 2
value = 3
value = 4
value = 5
pi = 00000000*/