检查输入是否已经输入到一个数组中

Question

我试图在代码中加入一个检查来查看是否输入了一个值。我的程序以（月日年）的格式对日期列表进行排序，当月份作为字符输入时。

下面是应该发生的一个例子。

3 - 要排序的n个日期的数量。

，随后在格式H日期（年月日）

01年1月1日

00年1月1日

99年2月28日

然后用户检查，如果日期已经被输入格式为（月日年）

最终输出：

日期按时间顺序排序

然后告诉用户，如果他们做了检查数据，他们 输入（这就是我需要帮助）

这就是我试图检查一个值是否被输入的方法。

int k; 
int input[j]; 
scanf("%d", &input[j]); 

for (i = 0; k < n; k++) { 
    if (ar[i] == input[j]) { 

     printf("Yes value is there"); 
    } 
    else { 

     printf("No value isn't"); 
    } 
} 

下面我发布了我的工作程序，没有尝试执行检查。运行这个只是返回按时间顺序排序的日期。

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

/* constants for max chars, max day, max year, max size */ 
enum { MAXC = 12, 
    MAX_DAY = 31, 
    MAX_YEAR = 12, 
    MAX_SIZE = 1000 }; 
typedef struct { 
    char month[MAXC]; /* either make static or allocate separately */ 
    unsigned day; 
    unsigned year; 
    int monthnum; 
} date; 

/* empty character remaining in stdin */ 
void empty_stdin() 
{ 
    int c; 
    while ((c = getchar()) != '\n' && c != EOF) { 
    } 
} 

int fix_year(int year) 
{ 
    if (year >= 90) 
     return 1900 + year; 
    return 2000 + year; 
} 

/* sort struct date on year */ 
int sort(const void* a, const void* b) 
{ 
    date* date1 = (date*)a; 
    date* date2 = (date*)b; 

    /*if (date2->year != date1->year) 
     return (date1->year > date2->year) - (date1->year < date2->year);*/ 

    int year1 = fix_year(date1->year); 
    int year2 = fix_year(date2->year); 
    //return year2 - year1; 

    //int month1 = date1->month; 
    //int month2 = date2->month; 

    if (date2->year != date1->year) { 
     return year2 - year1; 
    } 
    else if (date2->month != date1->month) { 
     int month1 = date1->month; 
     int month2 = date2->month; 

     return month2 - month1; 
    } 
    else if (date2->day != date1->day) { 
     //else sort day 
     int day1 = date1->month; 
     int day2 = date2->month; 

     /*int daycompare = date2->day - date1->day; 
    return -daycompare; 
    */ 

     return day2 - day1; 
    } 

    return 0; 
} 

/* output n elements of array of struct date */ 
void output(date* ar, int n) 
{ 
    int i; 

    printf("\nOutput sorted by year:\n\n"); 

    for (i = 0; i < n; i++) 
     printf(" %s %d %d\n", ar[i].month, ar[i].day, ar[i].year); 
} 

int main(void) 
{ 

    int i, n; 
    date* ar = NULL; 

    while (1) { /* obtain valid 'n', compare with using fgets below */ 

     int rtn; /* varaible to save return of scanf -- always validate */ 

     //printf ("Enter number of dates to be entered (between 1 & 1000): "); 
     if ((rtn = scanf("%d", &n)) != 1) { /* if conversion failed */ 
      if (rtn == EOF) { /* test for user cancelation of input */ 
       fprintf(stderr, "note: user canceled input, exiting.\n"); 
       return 0; 
      } /* otherwise simply an invalid input */ 
      fprintf(stderr, "error: invalid input.\n"); 
      goto tryagain; 
     } 

     if (n < 0) { /* invalid input < 0 */ 
      fprintf(stderr, "error: invalid input (n < 0).\n"); 
      goto tryagain; 
     } 

     if (n > MAX_SIZE) { /* invalid input > MAX_SIZE */ 
      fprintf(stderr, "error: invalid input (n > %d).\n", MAX_SIZE); 
      goto tryagain; 
     } 

     break; /* if we are here - we have a good value, break */ 

    tryagain:; /* label for goto to jump over break */ 

     empty_stdin(); /* empty characters that remain in input buffer */ 
    } 

    empty_stdin(); /* empty characters that remain in input buffer */ 

    /* allocate array of struct ar, n elements */ 
    if ((ar = malloc(sizeof *ar * n)) == NULL) { 
     fprintf(stderr, "error: virtual memory exhausted.\n"); 
     return 1; 
    } 

    /* provide format instructions */ 
    //printf ("Enter the date (month day year)\n" 
    // " format, e.g.: Jan 18 2017\n\n"); 

    for (i = 0; i < n; i++) { /* loop until all elements filled */ 

     char buf[MAX_DAY + 1] = "", ans[MAXC] = ""; 

     //printf (" date[%2d] : ", i + 1); /* prompt for input */ 

     /* if fgets return is NULL, EOF encountered */ 
     if (fgets(buf, MAX_DAY + 1, stdin) == NULL) { 
      fprintf(stderr, "note: user canceled input, exiting.\n"); 
      return 0; 
     } 

     if (*buf == '\n') { /* if first char is '\n', user just hit enter */ 
      printf("no input provided, quit (y/n)? "); 
      if (fgets(ans, MAXC, stdin) && (*ans == 'y' || *ans == 'Y')) 
       return 0; 
      else if (!*ans) { /* if ans NULL, EOF encountered */ 
       fprintf(stderr, "note: user canceled input, exiting.\n"); 
       return 0; 
      } 
     } 

     /* parse with sscanf, validate 3 conversion took place */ 
     if (sscanf(buf, "%11s %u %u", ar[i].month, &ar[i].day, &ar[i].year) != 3) { 
      fprintf(stderr, "error: invalid input.\n"); 
      continue; 
     } 

     /* only increment if valid sscanf conversion took place */ 
    } 

    //scanf("%d", &date_list[i].day); 
    qsort(ar, n, sizeof(date), sort); /* sort by year */ 

    output(ar, n); /* output results */ 

    free(ar); /* free ar - you allocate it, you free it */ 

    return 0; 
} 

Answer 1

int cday, cyear, cmonth, i; 
char smonth[MAXC]; 
scanf("%d %d %d",&month ,&day, &cyear); 
month_num_to_string(cmonth,smonth); 
for (i = 0; i < n; i++) { 
    if (ar[i].day== cday && ar[i].year== cyear && !strcmp(smonth, ar[i].month) { 
     break; 
    } 
} 
if (i<n) { 
    printf("Yes value is there\n"); 
} else { 
    printf("No value isn't\n"); 
} 

你可以做这样的事情， 但是你有一个小任务写入功能： month_num_to_string(cmonth,smonth);