将字符串中大小写互换

#include<stdio.h>#include<string.h>void myprintf(char *s1 ) {int i,c;i=0;while(s1[i]!='\0') {if((s1[i]>='a'&&s1[i]<='z'))printf("%c",s1[i]-32);else if(s1[i]>='A'&&s1[i]<='Z')printf("%c",s1[i]+32);elseprintf("%c",s1[i]);i++;}s1[i+1]='\0';}int main () {char s1[1000];scanf("%s\n",s1);myprintf(s1);return 0;}//一般情况下，这种题型不选择使用开关语句//ASCII值表的分布(主要记)//  "0~9"   48-57//  "a~z"   97-122//  "A~Z"   65~90