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#include <stdio.h>
//邻近字符串会自动连接,"A""B" 相当于"AB"
#define PRINT(FORMAT, VALUE)        \
    printf("The value of "   #VALUE   " is "\
            FORMAT "\n", VALUE)
#define PRINT_USE_NUMBER_SIGN(FORMAT, VALUE)        \
    printf("The value of "   #VALUE   " is "\
    #FORMAT "\n", VALUE)

//## 预处理时，将位于两边的符号连接成一个符号
#define ADD_TO_SUM(sum_number, value) \
    sum ## sum_number += value

int main ()
{
    int sum5 = 1;

    PRINT("%d", 3 + 1);
    PRINT_USE_NUMBER_SIGN(%d, 3 + 1);
    //宏参数前面加个Number Sign (#),预处理会将该宏参数转换为字符串
    //故PRINT_USE_NUMBER_SIGN中的%d不用加双引号

    ADD_TO_SUM(5, 10);
    printf("%d\n", sum5);

    return 0;
}


$ gcc -E 1.c
    printf("The value of " "3 + 1" " is " "%d" "\n", 3 + 1);
    printf("The value of " "3 + 1" " is " "%d" "\n", 3 + 1);
    sum5 += 10;
$ ./1
The value of 3 + 1 is 4
The value of 3 + 1 is 4
11