Wednesday, 18 January 2017

Counting the total number of occurrences of a character in a string(c programming examples)(c program examples)

Counting the total number of occurrences of a character in a string

There are several ways to get output. But a programmer needs a short way to get output. Because it saves a lot of time and in big projects, it will help in debugging process. In the first program we used a function named as 'allid()' but, in the second program, there are no functions just a small code with a few lines to get the same output of the above. The programming is very cool to do when you have passion in that.


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>
int allid(char *a,char c)
{
    int j=0,i;
     for(i=0;a[i]!='\0';i++)
    {
        if(c==a[i])
            j++;
    }   
    return j;
}
int main()
{
    char string[1000],c;
    int res;
    printf("enter any string\n");
    gets(string);
    printf("enter the character to find its total occurrences in the string\n");
    scanf("%c",&c);
    res=allid(string,c);
    if(res==0)
        printf("the character you have entered is not in the string\n");
    else
        printf("the total number of occurrences of \'%c\'is %d\n",c,res );
    return 0;
}



The output is as follows:



The above program can also be written as follows:

#include <stdio.h>
int main()
{
    char string[1000],c;
    int i,res=0;
    printf("enter any string\n");
    gets(string);
    printf("enter the character to find its total occurrences in the string\n");
    scanf("%c",&c);
    for(i=0;string[i]!='\0';i++)
    {
        if(c==string[i])
            res++;
    }
if(res==0)
printf("the character you have entered is not in the string\n");
else
    printf("the total number of occurrences of \'%c\'is %d\n",c,res );
    return 0;
}


Let me explain the code:

In both the codes the logic is same but the usage of logic is different in both the methods. In the first method, the logic is separated from the main function and it is derived as a new function named as 'allid()'. The function 'allid()' returns the value into the main function when it is called.


#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 string[1000],c;

The data type 'char' is used so that to handle the characters in the program. The array 'string[]' is used to carry the string and the variable 'c' is used to carry the character.

Logic in the program:

The logic in the program is to check the occurrence of the character in the string. The character entered by the user is stored in a variable and it is checked with each element in the string. If the equal operator satisfies then the value of 'j' increases by one representing how many times it is found in the string. If it is not in the string the value of 'j' remains as '0'. So the end lines of code check the value of 'res' to ensure that the character is found or not.


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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