// toupper.c#include <stdio.h>#include <string.h>#include <ctype.h>int main(){ char *s="Hello, World!"; int i; //clrscr(); // clear screen printf("%s\n",s); for(i=0;i<strlen(s);i++) { putchar(toupper(s[i])); } getchar(); return 0;}原文：http://www.cnblogs.com/loanhicks/p/6445624.html