Language: C++

#include<iostream>
#include<string.h>
int main(void){
    char s;
    scanf("%c",s);
    if(strcmp(s,'Sunny')==0){
        printf("Cloudy");
    }
    if(strcmp(s,'Cloudy')==0){
        printf("Rainy");
    }
    if(strcmp(s,'Rainy')==0){
        printf("Sunny");
    }
}

Compiler output:
a.cc:6:17: warning: multi-character literal with 5 characters exceeds 'int' size of 4 bytes
    6 |     if(strcmp(s,'Sunny')==0){
      |                 ^~~~~~~
a.cc:9:17: warning: multi-character literal with 6 characters exceeds 'int' size of 4 bytes
    9 |     if(strcmp(s,'Cloudy')==0){
      |                 ^~~~~~~~
a.cc:12:17: warning: multi-character literal with 5 characters exceeds 'int' size of 4 bytes
   12 |     if(strcmp(s,'Rainy')==0){
      |                 ^~~~~~~
a.cc: In function 'int main()':
a.cc:6:15: error: invalid conversion from 'char' to 'const char*' [-fpermissive]
    6 |     if(strcmp(s,'Sunny')==0){
      |               ^
      |               |
      |               char
In file included from a.cc:2:
/usr/include/string.h:156:32: note:   initializing argument 1 of 'int strcmp(const char*, const char*)'
  156 | extern int strcmp (const char *__s1, const char *__s2)
      |                    ~~~~~~~~~~~~^~~~
a.cc:6:17: error: invalid conversion from 'int' to 'const char*' [-fpermissive]
    6 |     if(strcmp(s,'Sunny')==0){
      |                 ^~~~~~~
      |                 |
      |                 int
/usr/include/string.h:156:50: note:   initializing argument 2 of 'int strcmp(const char*, const char*)'
  156 | extern int strcmp (const char *__s1, const char *__s2)
      |                                      ~~~~~~~~~~~~^~~~
a.cc:9:15: error: invalid conversion from 'char' to 'const char*' [-fpermissive]
    9 |     if(strcmp(s,'Cloudy')==0){
      |               ^
      |               |
      |               char
/usr/include/string.h:156:32: note:   initializing argument 1 of 'int strcmp(const char*, const char*)'
  156 | extern int strcmp (const char *__s1, const char *__s2)
      |                    ~~~~~~~~~~~~^~~~
a.cc:9:17: error: invalid conversion from 'int' to 'const char*' [-fpermissive]
    9 |     if(strcmp(s,'Cloudy')==0){
      |                 ^~~~~~~~
      |                 |
      |                 int
/usr/include/string.h:156:50: note:   initializing argument 2 of 'int strcmp(const char*, const char*)'
  156 | extern int strcmp (const char *__s1, const char *__s2)
      |                                      ~~~~~~~~~~~~^~~~
a.cc:12:15: error: invalid conversion from 'char' to 'const char*' [-fpermissive]
   12 |     if(strcmp(s,'Rainy')==0){
      |               ^
      |               |
      |               char
/usr/include/string.h:156:32: note:   initializing argument 1 of 'int strcmp(const char*, const char*)'
  156 | extern int strcmp (const char *__s1, const char *__s2)
      |                    ~~~~~~~~~~~~^~~~
a.cc:12:17: error: invalid conversion from 'int' to 'const char*' [-fpermissive]
   12 |     if(strcmp(s,'Rainy')==0){
      |                 ^~~~~~~
      |                 |
      |                 int
/usr/include/string.h:156:50: note:   initializing argument 2 of 'int strcmp(const char*, const char*)'
  156 | extern int strcmp (const char *__s1, const char *__s2)
      |                                      ~~~~~~~~~~~~^~~~