計(jì)算機(jī)二級(jí)C++輔導(dǎo):字符串內(nèi)部查找函數(shù)

char* strchr( const char* str, int chr );
    在str中查找第一次出現(xiàn)的chr，沒找到則返回0
    char* strrchr( const char* str, int chr );
    在str中查找最后一次出現(xiàn)的chr，沒找到則返回0
    char* strstr( const char* str, const char* substr );
    在str中查找第一次出現(xiàn)的substr，沒找到則返回0
    size_t strspn( const char* str, const char* chrset );
    在str中查找 只包含在chrset中的字符 的最開始的最長(zhǎng)字符數(shù)目
    strspn( "cabbage", "abc" ) == 5;
    strspn( "cabbage", "dc" ) == 1;
    strspn( "cabbage", "d" ) == 0;
    strspn( str, "abceg" ) == 7;
    char* strspnp( const char* str, const char* chrset );
    和strspn功能一樣，只是返回指針
    const char* str = "cabbage"
    strspnp( str, "abc" ) == str+5;
    strspnp( str, "dc" ) == str+1;
    strspnp( str, "d" ) == str+0;
    strspnp( str, "abceg" ) == 0; // 和strspn不一樣
    size_t strcspn( const char* str, const char* chrset );
    在str中查找第一次出現(xiàn)在chrset中的字符位置，沒找到則返回str結(jié)尾的''的位置
    strcspn( "xyzbxz", "abc" ) = 3
    strcspn( "xyzbxz", "xyz" ) = 0
    strcspn( "xyzbxz", "no match" ) = 6
    strcspn( "xyzbxz", "" ) = 6
    strcspn( "", "abc" ) = 0
    strcspn( "", "" ) = 0
    char* strpbrk( const char* str, const char* chrset );
    和strcspn功能一樣，只是返回指針
    strpbrk( "xyzbxz", "abc" ) = "xyzbxz"+3
    strpbrk( "xyzbxz", "xyz" ) = "xyzbxz"+0
    strpbrk( "xyzbxz", "no match" ) = 0 // 和strcspn不一樣
    strpbrk( "xyzbxz", "" ) = 0 // 和strcspn不一樣
    strpbrk( "", "abc" ) = 0 // 和strcspn不一樣
    strpbrk( "", "" ) = 0 // 和strcspn不一樣
    ------------------------
    假如想將 "123@456@789" 分割成 "123" "456" "789" 當(dāng)用 strchr
    假如想將 "123@#456@#789" 分割成 "123" "456" "789" 當(dāng)用 strstr
    假如想將 "123@456#789@#0" 分割成 "123" "456" "789" "" "0" 當(dāng)用 strcspn
    假如想將 "123@456#789@#0" 分割成 "123" "456" "789" "0" 當(dāng)用 strcspn/strspn