Monday, 16 January 2017

Finding the length of a string using string functions in C programming(c programming examples)(c program examples)

Finding the length of a string using string functions in C programming

The below programs are used to find the length of the string in an array. It means the total number of characters in the array. This is an example in C which covering the concept of finding the length of a string using string function. The first program uses only a loop. 

If you want to see this code with a perfect indentation, copy the code into "sublime text editor" and make sure that the type of code is set to 'c' at the bottom right of the window. After pasting the code press the command "ctrl+shift+P", you get a search box. Type "indentation" you get an option like this below the search box "Indentation: Reindent lines". Clink on that to get the code with indentation. 

The program is as follows:

#include <stdio.h>
main()
{
char text[1000];
int index=0;
gets(text);
while(text[index]!='\0')
{
index++;
}
printf("the length of '%s'=%d \n", text, index);
return 0;
}


The output is as follows:




Using "strlen" for finding the length of text:

#include <stdio.h>

#include <string.h>
main()
{
char text[1000];
int length;
gets(text);
length=strlen(text);
printf("the length of text %s is %d\n",text, length );
return 0;
}



#include <stdio.h>



The '#include' is a preprocessor directive which includes the source files inside the code. The 'stdio.h' is a standard input and output header file with several functions written in it. The functions like 'printf()''gets()' and 'scanf()' are work when we include 'stdio.h' header file. 

char text[1000];

The array 'text[]' is used to hold the string in it which is given by the user. The data type 'char' is used to carry the character data in the array.

int index=0;

The variable 'index' is declared to represent the size of the array. The value of 'index' is assigned with '0' to remove any other garbage value in it. The garbage value may occur errors in the output of the program.

gets(text);

The function 'gets()' assigns the input given by the user into the array 'text[]'. When we use this function you need to include the header file 'stdio.h' before the main function.

while(text[index]!='\0')
{
index++;
}

This a while loop which contains only condition in the parenthesis. Here in this loop, we are not declaring any other external variable to browse the elements of the array. The value of the variable 'index' itself helps in finding the end of the array. After finding the null character loop terminates and the execution jumps to next line of the program.

printf("the length of '%s'=%d \n", text, index);

The function 'printf()' prints the message and output. The symbol '%s' represents the string and the symbol '%d' represents the integer value which is in the variable index.

length=strlen(text);

The loop is replaced with this line instead of writing the conditions. It is a predefined function in the header file 'string.h' which help in this line. The output of the function 'strlen()' is stored in the variable 'length' which is declared in the second line of the second program.

#include <string.h>

'#include' is a preprocessor directive which includes the header files into the program. To add the header file 'string.h' we used the line "#include <string.h>". The header file 'string.h' contains the functions to do several operations on the string data. There are several functions in the header file 'string.h'. For example 'strlen()', 'strcmp()', 'strcat()', 'strcpy()' etc...
Each function is used for a particualr purpose.


Hence the problem is solved by using a program. Another program gets into the bucket.


C is a general-purpose programming language. It has been closely associated with the UNIX system where is was developed, since both the system and most of the programs that run on it are written in C. The language, however, is not tied to any one operating system or machine; and although it has been called a “system programming language” because it is useful for writing compilers and operating systems, it has been used equally well to write major programs in many different domains.(c programming examples)(c program examples)
Many of the important ideas of C stem from the language BCPL, developed by Martin Richards. The influence of BCPL on C proceeded indirectly through the language B, which was written by Ken Thompson in 1970 for the first UNIX system on the DEC PDP-7.(c programming examples)
BCPL and B are “typeless” languages. By contrast, C provides a variety of data types. The fundamental types are characters, and integers and floating point numbers of several sizes. In addition, there is a hierarchy of derived data types created with pointers, arrays, structures, and unions. Expressions are formed from operators and operands; any expression, including an assignment or a function call, can be a statement. Pointers provide for machine-independent address arithmetic.(c programming examples)(c program examples)
C provides the fundamental control-flow constructions required for well-structured programs: statement grouping, decision making (if-else), selecting one of a set of possible cases (switch), looping with the termination test at the top (while, for) or at the bottom (do), and early loop exit (break).(c programming examples)(c program examples)
Functions may return values of basic types, structures, unions, or pointers. Any function may be called recursively. Local variables are typically “automatic,” or created anew with each invocation. Function definitions may not be nested but variables may be declared in a block-structured fashion. The functions of a C program may exist I separate source files that are compiled separately. Variables may be internal to a function, external but know only within a single source file, or visible to the entire program.(c programming examples)(c program examples)
A preprocessing step performs macro substitution on program text, inclusion of other source files, conditional compilation.(c programming examples)(c program examples)
C  is a relatively “low level” language. This characterization is not pejorative; it simply means that C deals with the same sort of object that most computers do, namely characters, numbers, and addresses. These may be combined and moved about with the arithmetic and logical operators implemented by real machines.(c programming examples)(c program examples)
C provides no operations to deal directly with composite objects such as character strings, sets, lists, or arrays. There are no operations that manipulate an entire array or string, although structures may be copied as a unit. The language does not define any storage allocation facility other than static definition and the stack discipline provided by the local variables of functions; there is n heap or garbage collection. Finally, C itself provides no input/output facilities; there are no READ or WRITE statements, and no built-in file access methods. All of these higher-level mechanisms must be provided by explicitly called functions. Most C implementations have included a reasonably standard collection of such functions.(c programming examples)(c program examples)

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