C++如何把字符串中小写字母改成大写，大写该小写

#include<iostream>#include<cstring>usingnamespacestd;intmain(){chars[]="Thisisateststring";for(inti=0;i<strlen(s);i++){if(s[i]>='a'&&s[i]<='z')s[i]=s[i]-0x20;//转小写}cout<<s;}