Questions about the function of the strstr function

There is a connection because char * is very special, char * is actually to open up a constant memory to store a string, and then return the first address of this string, then the landlord finally said that if the search is successful, it will return a non-null return value, this address is actually the first address of the result If successful, then your strstr function has already written a search function, this pointer starts from the first character in the original string, and the pointer moves backwards one by one, If a substring is found, the current pointer is returned, which is actually the address of one of the characters of the original string.

Hopefully, you'll try to understand the concept of an opp object, and that's how we use strcpy(str1,strstr(s1,s2)) a lot of the time

string(n，"str"The function of the function is to return a function consisting of n charactersStrings

The method of expressing the functional relationship between two variables using an equation that contains mathematical relations is called the analytic method. The advantage of this approach is that it can concisely, accurately, and clearly represent functions and independent variables.

quantitative relationships between them; The disadvantage is that it often has to go through more complex operations when finding the corresponding value, and some functional relationships in practical problems may not be able to use the first balance expression.

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str function

When a number is converted into a string, there is always an empty space left in front of it to indicate the positive or negative. If number is positive, the returned string containing a leading space implies a positive sign.

Use the format function to convert values to the necessary format, such as date, time, currency, or other user-defined format. Unlike str, the format function does not contain leading spaces to place the plus or minus signs of number.

Note that the str function only looks at the period (.).is a valid decimal point. If you use a different decimal point (for example, for an international application, you can use cstr to convert numbers to strings.)

function string(n,"str"Raid shout) returns a string of n characters.

The method of expressing the functional relationship between two variables using an equation that contains mathematical relations is called the analytic method. The advantage of this method is that it can concisely, accurately and clearly represent the quantitative relationship between the function and the independent variable. The disadvantage is that it often has to go through more complex operations when finding the corresponding values, and some of the functional relationships in the field problem of real circles may not be expressed by expressions.

The C library function char *strcat(char *dest, const char *src) appends the string pointed to by src to the end of the string pointed to by dest.

Parameter: dest -- points to the target array, which contains a c string and is large enough to hold the appended string.

src -- points to the string to append, which does not overwrite the target string.

Return Value: The function returns a pointer to the final destination string dest.

An example demonstrates the use of the strcat() function.

#include #include int main ()

This example uses the str function to convert a number into a string. When converting a number to a string, the first bit of the string must be a space or a plus or minus sign.

dim mystringmystring = str(459) 'Return = str('Return = str('Return.

strstr(strcat(str1, str2), str3);It is used to connect str2 to the back of str1 to form a new string, and then find the position containing str3 in the new string, and at the same time return the string after that position in its entirety.

strcat(str1, str2) is to connect str2 to the end of str1, since strcat does not do string length checking, it must ensure that the remaining space of incoming str1 can be accommodated.

Under str2, for example:

char str1[100] = "hello";

char str2 = world;

Then strcat(str1, str2) returns the following result: helloworld

But if str1 length only"hello", there will be an unforeseen error.

strstr(str1, str2) will find str2 in str1 and return the remaining string, e.g. char str1 ="hello";

char str2 = "e";

Then strstr(str1, str2) returns the following result: ello

str(number)

The required number parameter is a long, which can contain any valid numeric expression.