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C++ Programming Code Examples

C++ > Algorithms Code Examples

Copy all the files and directory

/* Copy all the files and directory */ #include <windows.h> /* BOOL Copy(char r_szPath[1024], char r_szDir[1024]) { char l_szTemp[2048] = {0}; sprintf(l_szTemp,"%s\%s"r_szPath,r_szDir); if(IsDirectory( }*/ #include <stdio.h> #include<conio.h> BOOL __Copy(char r_szSrcPath[1024],char r_szDesPath[1024]) { WIN32_FIND_DATA FindFileData; HANDLE hFind; char l_szTmp[1025] = {0}; memcpy(l_szTmp,r_szSrcPath,1024); char l_szSrcPath[1025] = {0}; char l_szDesPath[1025] = {0}; memcpy(l_szSrcPath,r_szSrcPath,1024); memcpy(l_szDesPath,r_szDesPath,1024); char l_szNewSrcPath[1025] = {0}; char l_szNewDesPath[1025] = {0}; strcat(l_szTmp,"*"); hFind = FindFirstFile(l_szTmp, &FindFileData); if(hFind == NULL) return FALSE; do { if(FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) { if(strcmp(FindFileData.cFileName,".")) { if(strcmp(FindFileData.cFileName,"..")) { printf ("The Directory found is %s ", FindFileData.cFileName); sprintf(l_szNewDesPath,"%s%s\",l_szDesPath,FindFileData.cFileName); sprintf(l_szNewSrcPath,"%s%s\",l_szSrcPath,FindFileData.cFileName); CreateDirectory(l_szNewDesPath,NULL); __Copy(l_szNewSrcPath,l_szNewDesPath); } } } else { printf ("The File found is %s ", FindFileData.cFileName); char l_szSrcFile[1025] = {0}; char l_szDesFile[1025] = {0}; sprintf(l_szDesFile,"%s%s",l_szDesPath,FindFileData.cFileName); sprintf(l_szSrcFile,"%s%s",l_szSrcPath,FindFileData.cFileName); BOOL l_bRet = CopyFile(l_szSrcFile,l_szDesFile,TRUE); } } while(FindNextFile(hFind, &FindFileData)); FindClose(hFind); return TRUE; } int main(int argc, char *argv[]) { __Copy("C:\fcdb\","E:\sowmya\"); getch(); return 0; }

In while loop, condition is evaluated first and if it returns true then the statements inside while loop execute, this happens repeatedly until the condition returns false. When condition returns false, the control comes out of loop and jumps to the next statement in the program after while loop. The important point to note when using while loop is that we need to use increment or decrement statement inside while loop so that the loop variable gets changed on each iteration, and at some point condition returns false. This way we can end the execution of while loop otherwise the loop would execute indefinitely. A while loop that never stops is said to be the infinite while loop, when we give the condition in such a way so that it never returns false, then the loops becomes infinite and repeats itself indefinitely.

In computer programming, we use the if statement to run a block code only when a certain condition is met. An if statement can be followed by an optional else statement, which executes when the boolean expression is false. There are three forms of if...else statements in C++: • if statement, • if...else statement, • if...else if...else statement, The if statement evaluates the condition inside the parentheses ( ). If the condition evaluates to true, the code inside the body of if is executed. If the condition evaluates to false, the code inside the body of if is skipped.

Concatenate strings. The strcat() function in C++ appends a copy of a string to the end of another string. It is defined in <cstring> header file. Appends a copy of the source string to the destination string. The terminating null character in destination is overwritten by the first character of source, and a null-character is included at the end of the new string formed by the concatenation of both in destination. destination and source shall not overlap. The strcat() function takes two arguments: destination and source. This function appends a copy of the character string pointed to by source to the end of string pointed to by destination. The null terminating character at the end of destination is replaced by the first character of source and the resulting character is also null terminated.

The if...else statement executes two different codes depending upon whether the test expression is true or false. Sometimes, a choice has to be made from more than 2 possibilities. The if...else ladder allows you to check between multiple test expressions and execute different statements. In C/C++ if-else-if ladder helps user decide from among multiple options. The C/C++ if statements are executed from the top down. As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the C else-if ladder is bypassed. If none of the conditions is true, then the final else statement will be executed.

Compare two strings. Compares the C string str1 to the C string str2. This function starts comparing the first character of each string. If they are equal to each other, it continues with the following pairs until the characters differ or until a terminating null-character is reached. This function performs a binary comparison of the characters. For a function that takes into account locale-specific rules, see strcoll. The strcmp() function in C++ compares two null-terminating strings (C-strings). The comparison is done lexicographically. It is defined in the cstring header file.

Write formatted data to string. Composes a string with the same text that would be printed if format was used on printf, but instead of being printed, the content is stored as a C string in the buffer pointed by str. The size of the buffer should be large enough to contain the entire resulting string (see snprintf for a safer version). A terminating null character is automatically appended after the content. After the format parameter, the function expects at least as many additional arguments as needed for format.

#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.

The getch() is a predefined non-standard function that is defined in conio.h header file. It is mostly used by the Dev C/C++, MS- DOS's compilers like Turbo C to hold the screen until the user passes a single value to exit from the console screen. It can also be used to read a single byte character or string from the keyboard and then print. It does not hold any parameters. It has no buffer area to store the input character in a program. The getch() function does not accept any parameter from the user. It returns the ASCII value of the key pressed by the user as an input.

Copy block of memory. Copies the values of num bytes from the location pointed to by source directly to the memory block pointed to by destination. The underlying type of the objects pointed to by both the source and destination pointers are irrelevant for this function; The result is a binary copy of the data. The function does not check for any terminating null character in source - it always copies exactly num bytes. To avoid overflows, the size of the arrays pointed to by both the destination and source parameters, shall be at least num bytes, and should not overlap (for overlapping memory blocks, memmove is a safer approach).

A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.

If graph has no "Odd Degree Vertex", there is at least one "Eulerian Circuit". If graph as two vertices with odd degree, there is no Eulerian Circuit but at least one Eulerian Path. If graph

Using the bellman-ford algorithm to find the shortest path between two vertices assuming that negative size edges exist in the graph. A Program to find the 'shortest path' algorithm

Internal method to test if a positive number is prime. Not an efficient algorithm and Internal method to return a 'prime number' at least as large as n. Assumes "n > 0". Insert item x into