求指点！vigenere密码程序无法输出结果

#include<stdlib.h>
#include<stdio.h>
#include<string.h>
void Encry()
{
char key[100];
char ch, temp;
int L, i = 0, j = 0;
if (getchar() == “\n”)
temp = ” “;
printf(“请输入密钥:”);
gets_s(key,100);
L = strlen(key);
printf(“请输入明文:”);
while ((ch = getchar()) != “\n”)
{
if (ch = ” “)
{
i++;
continue;
}
if (ch >= “a”&&ch <= “z”)
{
printf(“%c”, (ch + key[j%L] – “a” – “a”) % 26 + “A”);
j++;
}
if (ch >= “A”&&ch <= “Z”)
{
printf(“%c”, (ch + key[j%L] – “a” – “A”) % 26 + “A”);
j++;
}
if (j%L == 0)
printf(” “);
i++;
}
putchar(ch);
}
void Decry()
{
char key[100];
char ch, temp;
int L, i = 0, j = 0;
if (getchar() == “\n”)
temp = ” “;
printf(“请输入密钥:”);
gets_s(key,100);
L = strlen(key);
printf(“请输入密文:”);
while ((ch = getchar())!= “\n”)
{
if (ch == ” “)
{
i++;
continue;
}
if (ch >= “A”&&ch <= “Z”)
{
printf(“%c”, (ch – key[j%L] – “A” + “a” + 26) % 26 + “a”);
j++;
}
if (j%L == 0)
printf(“”);
i++;
}
putchar(ch);
}
int Exit()
{
exit(0);
}
int main()
{
char ch;
for (;;)
{
printf(“请输入操作 e:加密 d:解密 q:退出 “);
ch = getchar();
if (ch == “e” || ch == “E”)
Encry();
else if (ch == “d” || ch == “D”)
Decry();
else if (ch == “q” || ch == “Q”)
Exit();
else
{
printf(“输入命令错误”);
putchar(getchar());
continue;
}
}
return 0;
}

解决方案

#include<stdlib.h>
#include<stdio.h>
#include<string.h>
void Encry()
{
    char key[100];
    char ch, temp;
    int L, i = 0, j = 0;
    if (getchar() == "\n")
        temp = " ";
    printf("请输入密钥:");
    gets_s(key,100);
    //gets(key);
    L = strlen(key);
    printf("请输入明文:");
    while ((ch = getchar()) != "\n")
    {
        if (ch == " ")
        {
            i++;
            continue;
        }
        if (ch >= "a"&&ch <= "z")
        {
            printf("%c", (ch + key[j%L] - "a" - "a") % 26 + "A");
            j++;
        }
        if (ch >= "A"&&ch <= "Z")
        {
            printf("%c", (ch + key[j%L] - "a" - "A") % 26 + "A");
            j++;
        }
        if (j%L == 0)
            printf(" ");
        i++;
    }
    putchar(ch);
}
void Decry()
{
    char key[100];
    char ch, temp;
    int L, i = 0, j = 0;
    if (getchar() == "\n")
        temp = " ";
    printf("请输入密钥:");
    gets_s(key,100);
    //gets(key);
    L = strlen(key);
    printf("请输入密文:");
    while ((ch = getchar())!= "\n")
    {
        if (ch == " ")    /*此处不是赋值，而是判断 == */
        {
            i++;
            continue;
        }
        if (ch >= "A"&&ch <= "Z")
        {
            printf("%c", (ch - key[j%L] - "A" + "a" + 26) % 26 + "a");
            j++;
        }
        if (j%L == 0)
            printf("");
        i++;
    }
    putchar(ch);
}
int Exit()
{
    exit(0);
}
int main()
{
    char ch;
    for (;;)
    {
        printf("请输入操作  e:加密 d:解密 q:退出 ");
        ch = getchar();
        if (ch == "e" || ch == "E")
            Encry();
        else if (ch == "d" || ch == "D")
            Decry();
        else if (ch == "q" || ch == "Q")
            Exit();
        else
        {
            printf("输入命令错误");
            putchar(getchar());
            continue;
        }
    }
    return 0;
}

有一处问题，比较容易出错误。详见代码注释；