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C Programming Code Examples

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vowels counting using vfork

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/* vowels counting using vfork */ #include<stdio.h> #include<sys/types.h> int main() { int j,n,a,i,e,o,u; char str[50]; a=e=i=o=u=0; pid_t pid; if((pid=vfork())<0) { perror("FORK ERROR"); exit(1); } if(pid==0) { printf(" Counting Number of Vowels using VFORK"); printf(" -------- ------ -- ------ ----- -----"); printf(" Enter the String:"); gets(str); _exit(1); } else { n=strlen(str); for(j=0;j<n;j++) { if(str[j]=='a' || str[j]=='A') a++; else if(str[j]=='e' || str[j]=='E') e++; else if(str[j]=='i' || str[j]=='I') i++; else if(str[j]=='o' || str[j]=='O') o++; else if(str[j]=='u' || str[j]=='U') u++; } printf(" Vowels Counting"); printf(" ------ --------"); printf(" Number of A : %d",a); printf(" Number of E : %d",e); printf(" Number of I : %d",i); printf(" Number of O : %d",o); printf(" Number of U : %d",u); printf(" Total vowels : %d ",a+e+i+o+u); exit(1); } }

#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. Here are the two types of file that can be included using #include:

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.

Print error message. Interprets the value of errno as an error message, and prints it to stderr (the standard error output stream, usually the console), optionally preceding it with the custom message specified in str. errno is an integral variable whose value describes the error condition or diagnostic information produced by a call to a library function (any function of the C standard library may set a value for errno, even if not explicitly specified in this reference, and even if no error happened), see errno for more info.

Get string length. Returns the length of the C string str. The length of a C string is determined by the terminating null-character: A C string is as long as the number of characters between the beginning of the string and the terminating null character (without including the terminating null character itself).

In C, the "main" function is treated the same as every function, it has a return type (and in some cases accepts inputs via parameters). The only difference is that the main function is "called" by the operating system when the user runs the program. Thus the main function is always the first code executed when a program starts. main() function is a user defined, body of the function is defined by the programmer or we can say main() is programmer/user implemented function, whose prototype is predefined in the compiler. Hence we can say that main() in c programming is user defined as well as predefined because it's prototype is predefined. main() is a system (compiler) declared function whose defined by the user, which is invoked automatically by the operating system when program is being executed.

Writes the C string pointed by format to the standard output (stdout). If format includes format specifiers (subsequences beginning with %), the additional arguments following format are formatted and inserted in the resulting string replacing their respective specifiers. printf format string refers to a control parameter used by a class of functions in the input/output libraries of C programming language. The string is written in a simple template language: characters are usually copied literally into the function's output, but format specifiers, which start with a % character, indicate the location and method to translate a piece of data (such as a number) to characters. "printf" is the name of one of the main C output functions, and stands for "print formatted". printf format strings are complementary to scanf format strings, which provide formatted input (parsing). In both cases these provide simple functionality and fixed format compared to more sophisticated and flexible template engines or parsers,

The for loop is used in the case where we need to execute some part of the code until the given condition is satisfied. The for loop is also called as a per-tested loop. It is better to use for loop if the number of iteration is known in advance. The for-loop statement is a very specialized while loop, which increases the readability of a program. It is frequently used to traverse the data structures like the array and linked list.

Get string from stdin. Reads characters from the standard input (stdin) and stores them as a C string into str until a newline character or the end-of-file is reached. The newline character, if found, is not copied into str. A terminating null character is automatically appended after the characters copied to str. Notice that gets is quite different from fgets: not only gets uses stdin as source, but it does not include the ending newline character in the resulting string and does not allow to specify a maximum size for str (which can lead to buffer overflows).

An expression containing logical operator returns either 0 or 1 depending upon whether expression results true or false. Logical operators are commonly used in decision making in C programming. These operators are used to perform logical operations and used with conditional statements like C if-else statements.

The exit() function is used to terminate a process or function calling immediately in the program. It means any open file or function belonging to the process is closed immediately as the exit() function occurred in the program. The exit() function is the standard library function of the C, which is defined in the stdlib.h header file. So, we can say it is the function that forcefully terminates the current program and transfers the control to the operating system to exit the program. The exit(0) function determines the program terminates without any error message, and then the exit(1) function determines the program forcefully terminates the execution process.




C program to input hexadecimal number and convert it to Decimal number. Hexadecimal number system is a base 16 number system. It uses 16 symbols to represent all number i.e.


C program, using recursion, 'Performs Merge' sort. A Merge Sort is a sorting algorithm with 'Complexity of O(nlogn)'. It is used for sorting numbers, structure, files. Perform Merge Sort

'StrrChr' is similar to the function 'StrChr', the only difference is that it searches the string in "Reverse Order", would have understood why we have extra r in 'strrchr', yes you guessed it


C program to find area of Parallelogram. This C code Calculates the 'Area of Parallelogram'. The formula used in this c program are Area = b*a where b is the length of any base, a is the



Swap two number using bitwise operator in C programming. There are tons of discussions going around the internet to swap 2 numbers without using temporary variable. We can...