复制代码 代码如下:
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

int main(void)
{
int length, i;
char string[20]= "this is a string";

length = strlen(string);
for (i=0; i<length; i++)
{
string[i] = toupper(string[i]);
}

printf("%s\n",string);
system("pause");
return 0;
}