C언어 활용 문제 : 글자수 세는 프로그램

#include 

main()
{
      int quit=0;
      while (quit==0)
      {
            printf("문장을 입력하시오:");
            int wordnum=0;
            char c='\0';
            char lastletter='\0'; 
            while(quit==0)
            {
                     lastletter=c;
                     c=getchar();
                     if(c='\n') /*엔터가 입력되면 글자수 세기*/ 
                     {
                                printf("글자수:%d\n",wordnum);
                                printf("프래그램을 종료하시려면 1을 입력 \n");
                                switch(quit)
                                {
                                             case '0' :
                                                  break;
                                             case '1' :
                                                  printf("시스템 종료\n");
                                                  quit=1;
                                                  break;
                                             default :
                                                     printf("잘못입력하셨습니다.\n");
                                }
                     break; /*만약 엔터가 아니면 wordnum 계속 세기*/ 
                     }
                     if(wordnum==0) /*만약 첫글자라면 앞에 아무것도 없으므로 스페이스바가 아닌 다른 문자가 c에 getchar()로 입력되면 wordnum +1*/ 
                                   if(c!=' ')
                                           wordnum+=1;
                     else
                         if(lastletter==' '&&c!=' ')
                                          wordnum+=1; /*만약 스페이스 다음에 (스페이스가 아닌) 문자가 오면 wordnum +1*/                                   
            }
      }
}

 

**오류났어 ㅠㅠ**

 

#include 

main()
{
      int quit=0;
      while (quit==0)
      {
            printf("문장을 입력하시오:");
            int wordnum=0;
            char c='\0';
            char lastletter='\0';
            while(1)
            {
                     lastletter=c;
                     c=getchar();
                     if(lastletter=='\0' && c!=' ')
                          wordnum+=1;
                     else if(lastletter==' ' && c!=' ')
                          wordnum+=1;
                     else if(c='\n') /*엔터가 입력되면 글자수 세기*/
                     {
                                char sw;
                                printf("글자수:%d\n",wordnum);
                                printf("프래그램을 종료하시려면 1을 입력하시고 계속하시려면 0을 입력하세요. \n");
                                sw = getchar();
                                
                                 switch(sw) /*sw를 quit으로 대체하면 안된다.  */ 
                                {
                                             case '0' :
                                                  break;
                                             case '1' :
                                                  printf("시스템 종료\n");
                                                  quit=1;
                                                  break;
                                             default :
                                                  printf("잘못입력하셨습니다.\n"); 
                                }/*만약 엔터가 아니면 wordnum 계속 세기*/ 
                     break;
                     }
            }
      }
}