实验结论

#include<stdio.h>
int main(){
    int days;
    
    printf("输入一个整数：\n");
    scanf("%d",&days);
    
    if(1<=days&&days<=5)
      printf("workdays,fighting\n");
    else if(days==6||days==7)
      printf("weekend,relax~\n");
    else
      printf("0oops,not in 1~7\n");
      
    return 0; 
}

#include<stdio.h>
int main(){
    char ch;
    
    printf("输入一个字符：\n");
    scanf("%c",&ch);
    
    if(ch>=‘a‘&&ch<=‘z‘)
      printf("%c\n",ch=ch-32);
    else
      printf("%c",ch);
    
    
    return 0; 
}