谁能看出这有什么问题(C 中与时间相关的函数)

Question

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

static struct tm createDate(unsigned day, unsigned mon, int year) {
       struct tm b = {0,0,0,day,mon-1,year-1900}; return b; 
}

static int dateExceeded(unsigned day, unsigned mon, int year) {
    struct tm b = createDate(day,mon,year); 
    time_t y = mktime(&b), now; 
    time(&now);  // error C2143: syntax error : missing ';' before 'type'
    double diff = difftime(y, now) / (60 * 60 * 24);  // error C2065: 'diff' : undeclared identifier
    return (diff < 0); 
}

static void randomEvent(){
    srand(time(NULL));
    if ( rand()%10) {
            printf("Do something here\n"); // C2143: syntax error : missing ';' before 'type'
  } 
}

Answer 1

如果将其编译为 C89 代码，则应在 block 的开头声明变量。您不能在 block 的中间声明 double diff:

static int dateExceeded(unsigned day, unsigned mon, int year) {
    double diff;
    struct tm b = createDate(day,mon,year); 
    time_t y = mktime(&b), now; 
    time(&now); 
    diff = difftime(y, now) / (60 * 60 * 24);
    return (diff < 0); 
}