C + + array, string manipulation

One, array manipulation

1. Initialization of arrays
1-1 initialization of one-dimensional arrays:
Standard way one: int value[100]; Value[i] has a variable value, not initialized
Standard way two: int value[100] = {+}; Value[0] and Value[1] values of 1 and 2, respectively, and no defined value[i>1]
Pointer mode: int* value = new Int[n]; Not initialized
delete []value; Must not forget to delete the array space
1-2 initialization of two-dimensional arrays:
Standard way one: int value[9][9]; VALUE[I][J] has a variable value, not initialized
Standard way two: int value[9][9] = {{1,1},{2}};//value[0][0,1] and value[1][0] values are initialized, others initialized to 0
Pointer mode one: INT (*value) [n] = new Int[m][n];
delete []value; n must be a constant, call intuitive. Not initialized
2. Array copy
Header file #include<string.h>
int a[10]={34,56,4,10,77,51,93,30,5,52};
int b[10];
memcpy (b,a,sizeof (b));
3. Assigning values to arrays
Header file #include<string.h>
int A[50];
memset (A,0,sizeof (a));
4. Array sorting
Introduction of header File #include<algorithm>
int a[] = {8, 4, 5, 6, 8, 0, 11};
Sort (A, a + 7);
5. Array length
sizeof (Array)/sizeof (array[0]);

Second, string manipulation

C++:

Header file #include<string>

String str;

1. String length

Len = Str.length ();

Len = Str.size ();

2. String comparisons

can be directly compared

You can also:

Str1.compare (STR2);

Str1.compare (POS1,LEN1,STR2,POS2,LEN2); The value is negative, 0, positive.

Nops length to the end.

3. Additional

STR1 + = str2;

Or

Str1.append (STR2);

Str1.append (STR2.POS2,LEN2);

4. String extraction

STR2 = Str1.substr ();

str2 = Str1.substr (POS1);

str2 = Str1.substr (POS1,LEN1);

5. String Search

where = Str1.find (STR2);

where = Str1.find (STR2,POS1); POS1 is starting with the first of the str1.

where = Str1.rfind (STR2); Search from the back forward.

6. Inserting a string

is not an assignment statement.

Str1.insert (POS1,STR2);

Str1.insert (POS1,STR2,POS2,LEN2);

Str1.insert (Pos1,numchar,char); NumChar is the number of insertions, Char is the character to be inserted.

7. Replacing strings

Str1.replace (POS1,STR2);

Str1.replace (POS1,STR2,POS2,LEN2);

8. Delete a string

Str.erase (Pos,len)

Str.clear ();

9. Exchanging strings

Swap (STR1,STR2);

C + + array, string manipulation