写了下面两段程序， 第一段用char型变量作控制变量，编译通过但运行不正确，无法控制程序，而第二段程序仅仅把char换位int（3行标有modified，其余代码相同），就可以达到控制的目的。 请教下，第一段错在哪里呢？想用字符或字符串控制的话，应该怎么写呢？

谢谢~


#include<stdio.h>
#include<string.h>

main()
{
    int input;
    char contr;

    char *month[13] = {"Illegal month", "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

    while (contr!='N'&& contr!='n')
    {
        printf("Input a number for month:\n");
        scanf("%d",&input);

        if (input<1||input>12)
             puts(month[0]);
        else
            puts(month[input]);

        printf("Want to continue?(y or n)\n");
        scanf("%c", &contr);
    }

}
////////////////////////////////////////

#include<stdio.h>
#include<string.h>

main()
{
    int input;
    int contr;      // modified

    char *month[13] = {"Illegal month", "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

    while (contr!=1)
    {
        printf("Input a number for month:\n");
        scanf("%d",&input);      // modified

        if (input<1||input>12)
             puts(month[0]);
        else
            puts(month[input]);

        printf("Want to continue?\n");
        scanf("%d", &contr);       // modified

    }

}

#include<stdio.h>
#include<string.h>

main()
{
    int input;
    char contr;

    char *month[13] = {"Illegal month", "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

    while (contr!='N'&& contr!='n')
    {
        printf("Input a number for month:\n");
        scanf("%d",&input);

        if (input<1||input>12)
             puts(month[0]);
        else
            puts(month[input]);

        printf("Want to continue?(y or n)\n");
        scanf(" %c", &contr);  //空一下格 因为你上次输入时候会带上一个回车  下次就直接吧回车读取了  scanf陷阱多多
    }

}

#include<stdio.h>

int main(void) {
    int input;

    char *month[13]={"Illegal month", "Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

        do {
        printf("Input a number for month:\n");
        scanf("%d",&input);

        if (input<1||input>12)
             puts(month[0]);
        else
            puts(month[input]);

        printf("Want to continue?(y or n)\n");
                getchar();
    }while(getchar()!='n');

        return 0;

}

谢谢楼上2位的回答~