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("%sn",string);

system("pause");

return 0;

}