打印与适当输入相对应的月份

Question

我必须编写一个程序,用户使用两个整数a和b,其中a对应于一年中的月份(1 = jan,2 = feb等).该程序必须打印"a"和随后的"b"月份之后的月份.这就是我到目前为止所做的,但是对于我输入的每两个整数,我总是得到相同的输出:"1月,2月".任何帮助表示赞赏.

#include<stdio.h>

        enum month {jan,feb,mar,apr,may,jun,jul,aug,sep,oct,nov,dec}; /*This
allows yoou to name a finite set and to declare identifiers*/
        typedef enum month      month;

month next_month(month M)  /*this is a function definition*/
{
        switch (M) /* like an if-else statement, if this month is true goto the M=month you chose*/
        {
        case  jan:
                M=feb;break;
        case  feb:
                M=mar;break;
        case  mar:
                M=apr;break;
        case apr:
                M=may;break;
        case may:
                M=jun;break;
        case jun:
                M=jul;break;
        case jul:
                M=aug;break;
        case aug:
                M=sep;break;
        case sep:
                M=oct;break;
        case oct:
                M=nov;break;
        case nov:
                M=dec;break;
        case dec:
                M=jan;break;
        }
        return M;
}
void print_month (month M)  /*this is a function definition*/
{
        switch (M)  /* like an if-else statement, if this month is true goto the M=month you chose*/
        {
        case jan:
                printf("January");break;
        case feb:
                printf("February");break;
        case mar:
                printf("March");break;
        case apr:
                printf("April");break;
        case may:
                printf("May");break;
        case jun:
                printf("June");break;
        case jul:
                printf("July");break;
        case aug:
                printf("August");break;
        case sep:
                printf("September");break;
        case oct:
                printf("October");break;
        case nov:
                printf("November");break;
        case dec:
                printf("December");break;
        }
}
int main(void)
{
        month M, N, sat;
        printf("Please enter two integers:\n");
        scanf("%d%d", &M, &N);
        for (M = jan; M <= N; ((int)M++))
        {
                printf(" ");
                print_month(M);  /*function call to print month*/
                printf(" ");
                print_month(next_month(M));  /*function call to print previous month*/
                putchar('\n');
                return;
        }
}

Answer 1

你有这个主要的

    scanf("%d%d", &M, &N);
    for (M = jan; M <= N; ((int)M++))
    {
         /* ... */
    }

因此......在scanf行中,您将M(和N)更改为用户提供的值,
然后将M设置为jan有效地丢失用户选择的值.

你需要检查你的方式.

Answer 2

我对改进程序的建议是将switch语句替换为月份名称数组.编程和阅读会容易得多.

每当您可以用数据结构替换代码时,这通常是一个很大的改进.无论何时进行编程,这都需要记住和使用.

所以按照我的建议使用月份数组看起来有点像这样:

#include <stdio.h>

const char* months[12] = {
 "January", "February", "March", "April", "May", "June",
 "July", "August", "September", "October", "November", "December"
};

int main(void)
{
    int m;
    printf("Enter month: ");
    scanf("%d", &m);
    if( 1 <= m && m <= 12 ) {
        printf("%s\n", months[m-1]);
    }
    return 0;
}

Answer 3

return 表示从当前函数返回,因此在for循环的第一次迭代结束时,从main函数返回,程序退出.