C Programming Code Examples
C > Strings Code Examples
String operator: get length, compare and find a char
/* String operator: get length, compare and find a char */
#include <stdio.h>
#include <string.h>
int main(void)
{
char s1[80], s2[80];
gets(s1);
gets(s2);
printf("lengths: %d %d\n", strlen(s1), strlen(s2));
if(!strcmp(s1, s2))
printf("The strings are equal\n");
strcat(s1, s2);
printf("%s\n", s1);
strcpy(s1, "Happy Codings\n");
printf(s1);
if(strchr("Happy", 'p'))
printf("p is in Happy\n");
if(strstr("hi there", "hi"))
printf("found hi");
return 0;
}
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.
Locate substring. Returns a pointer to the first occurrence of str2 in str1, or a null pointer if str2 is not part of str1. The matching process does not include the terminating null-characters, but it stops there. The function returns pointer to the first occurrence of the matched string in the given string. It is used to return substring from first match till the last character. The strstr() function searches the string str1 for the first occurrence of the string str2 (not counting str2's terminating null character). The return value is a pointer to the first character in the first occurrence in str1 of the sequence contained in str2, or a null pointer if there is no such occurrence. If str2 points to an empty string, then strstr() returns the value of its first argument, str1.
#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:
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).
The if-else statement is used to perform two operations for a single condition. The if-else statement is an extension to the if statement using which, we can perform two different operations, i.e., one is for the correctness of that condition, and the other is for the incorrectness of the condition. Here, we must notice that if and else block cannot be executed simiulteneously. Using if-else statement is always preferable since it always invokes an otherwise case with every if condition.
Concatenate strings. 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.
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.
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.
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,
Locate first occurrence of character in string. Search for a given character in a string. Returns a pointer to the first occurrence of character in the C string str. The terminating null-character is considered part of the C string. Therefore, it can also be located in order to retrieve a pointer to the end of a string. The strchr() function returns a pointer to the first occurrence of the character value character in the string addressed by str. If there is no such character in the string, strchr() returns a null pointer. If character is a null character ('\0'), then the return value points to the terminator character of the string addressed by str.
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).
Copy string. Copies the C string pointed by source into the array pointed by destination, including the terminating null character (and stopping at that point). To avoid overflows, the size of the array pointed by destination shall be long enough to contain the same C string as source (including the terminating null character), and should not overlap in memory with source.
C program to find substring of string without using 'Library Function'. Accept input is state forward step. Call user 'defined function' and consider following strings are entered by the
C language input any number from user and count number of trailing zeros in the given number using bitwise operator. How to find total number of trailing zeros in any given...
Arithmetic operator performs mathematical operations such as addition, subtraction and multiplication on numerical values (constants and variables). C Program to demonstrate...
