#include <stdio.h> int main() { char ch=0; while(~scanf(" %c",&ch)) { if(isupper(ch)) printf("%c\n",tolower(ch)); else if(islower(ch)) printf("%c\n",toupper(ch)); } return 0; }
#include <stdio.h> int main() { char ch; while(scanf("%c\n",&ch)!=EOF) { { if(ch>='a'&&ch<='z') {ch=toupper(ch); printf("%c\n",ch);} else if(ch>='A'&&ch<='Z') {ch=tolower(ch); printf("%c\n",ch);} } } return 0; } //养成好习惯,if语句后面要有括号,超过一行不打括号会报错;
#include<stdio.h> int main() { int ch; while((ch=getchar())!=EOF){ getchar(); if(ch>=65 && ch<=90){ ch+=32; putchar(ch); } else if(ch>=97 && ch<=122){ ch-=32; putchar(ch); } else continue; printf("\n"); } return 0; }