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如果机器是对 int 类型数使用算术右移, 返回 1, 其他返回 0
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#include <stdio.h> | |
/* | |
* CSAPP exercise 2.62 | |
* */ | |
/* | |
* 如果机器是对 int 类型数使用算术右移, 返回 1, 其他返回 0 | |
* */ | |
int int_shifts_are_arithmetic(); | |
/* | |
* 正数返回 1, 负数返回 0 | |
* */ | |
int is_positive(int x); | |
int main() { | |
printf("%d \n", int_shifts_are_arithmetic()); | |
return 0; | |
} | |
int int_shifts_are_arithmetic() { | |
int shift = (sizeof(int) << 3) - 1; | |
return !is_positive(((1 << shift) >> 1)); | |
} | |
int is_positive(int x) { | |
int shift = (sizeof(int) << 3) - 1; | |
return !((x >> shift) & 1); | |
} |
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