1.獲取路徑下的文件名
char * FindFileName(char * s)
{
int len;
char *tmp=NULL;
ASSERT(s != NULL);
for (len=strlen(s); len>0;len--)
{
if((s[len]=='/') ||(s[len]=='//'))
{
tmp = &s[len+1];
break;
}
}
return tmp;
}
2.把整型轉化為字符型
char * i2a(int n, char *s)
{
int i, sign;
ASSERT(s != NULL);
if ((sign = n) < 0)
{
n = -n; //轉為正數,利於取位
}
do
{
s[i++] = n % 10 + '0';
}
while ((n /= 10) > 0)
if (sign < 0)
{
s[i++] = '-';
}
s[i] = '/0';
reverse(s);
}
3.把字符型轉為整型
int a2i(char * s)
{
int i, n, sign;
ASSERT(s != NULL);
for (i = 0; s[i] == ' '; i++)
{
NULL; //如果字串前有空格,跳過所有空格
}
sign = (s[i] == '-') ?: -1 : 1;
if (s[i] == '+' || s[i] == '-')
{
i++; //判斷是正整數串還是負整數串
}
for (n = 0; s[i] > = '0' && s[i] <= '9'; i++)
{
n = 10 * n + (s[i] - '0');
}
return sign*n;
}
4.輸出字符串倒文,不能動態分配內存
char * reverse(char * s)
{
int c, i, j;
ASSERT(s != NULL);
for (i = 0, j = strlen(s) - 1; i < j; i++, j--)
{
c = s[i];
s[i] = s[j];
s[j] = c;
}
return s;
}
5.查找子串是否存在
int strindex(char *str,char *searchstr)
{
int end, i, j;
ASSERT((str != NULL) && (searchstr != NULL));
//計算結束位置
end = strlen(str) - strlen(searchstr);
if ( end > 0 )
{
for ( i = 0; i <= end; i++ )
{
for ( j = i; str[j] == searchstr[j-i]; j++ )
{
if ( searchstr[j-i+1] == '/0' ) /* 子字符串字結束 */
{
return i + 1; /* 找到了子字符串 */
}
}
}
}
return -1;
}