http://www.eyny.com/viewthread.php?tid=5677820

gistfile1.c

#include <stdio.h>
#include <stdlib.h>
#define BUFFERSIZE 1024
//
int main(int argc, char* argv[])
{
	char* ptr = NULL;
	char* pReader = NULL;
	int i = 0, counter = 0;
	// 動態配置記憶體
	ptr = (char*) malloc(BUFFERSIZE * sizeof(char));
	printf("Input a string: "), gets(ptr);
	pReader = ptr;
	for (; *(pReader + i) != NULL; i ++)
	{
		if ( *(pReader + i) != 0x20 )
		{
			counter ++;
		}
	}
	// 釋放記憶體
	free(ptr);
	pReader = NULL;
	// 顯示字數
	printf("Letters = %d\n", counter);
	system("PAUSE");
	return (0);
}