Upper case to lower case of converting letters in C programming(c programming examples)(c program examples)

Upper case to lower case of converting letters in C programming

This is an example in C programming which is written on the base of loops and conditions. In the second program, we use only one function to get output. Both the outputs from two program are same. The function 'strlwr()' is a predefined function in the header file 'string.h' which is used to convert the upper case of a letter to its lower case.
The both programs are as follows:
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. 


1.Without any string function:

#include <stdio.h>
main()
{
char a[1000];
int i;
printf("enter any string\n");
gets(a);
for(i=0;a[i]!='\0';i++)
{
if(a[i]>=65 && a[i]<=90)
a[i]=a[i]+32;
}
printf("the lower case of the given string is as follows:\n");
for(i=0;a[i]!='\0';i++)
printf("%c",a[i] );
return 0;
}


2. With string function:


#include <stdio.h>
#include <string.h>
main()
{
char a[1000];
printf("enter any string\n");
gets(a);
strlwr(a);
printf("the lower case of the given string is '%s'\n",a );
return 0;
}


The output is as follows;

#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 a[1000];

Here we declare only one array 'a[]' to store the string entered by the user. And the data type used is 'char' which carries the character type data.

printf("enter any string\n");

gets(a);

The two predefined functions 'printf()' and 'gets()' are included in the 'stdio.h' header file. These lines are executed with the help of 'stdio.h' header file. The function 'printf()' prints the message "enter any string". The function 'gets()' assigns the string into the array 'a[]'.

for(i=0;a[i]!='\0';i++)

{

if(a[i]>=65 && a[i]<=90)

a[i]=a[i]+32;

}

We take a for loop in this logic. We initiate the value of 'i' with '0'. The condition is " a[i]!='\0' " used so that the iterations will carry on up to the last character of the array. The body of loop is an 'if condition'. According to ASCII values, a character in between the values 65 and 90 represents the Upper case of alphabetic letters. The difference between a lower case and upper case of a particular letter is 32. The condition checks whether the value of the character is in between 65 and 90. If it is satisfied the body of 'if condition' is executed. The value of the character is increased by 32 to get its lower case letter. And it is saved in the same compartment of the array. 

for(i=0;a[i]!='\0';i++)
printf("%c",a[i] );

This loop prints the string on the output screen after conversion.

Second Program:
strlwr(a);

A single line of code without any initiation or conditions or increments or decrements converts the case of the letter. The function 'strlwr()' is a string function which is predefined in the header file 'string.h'. The syntax of the function is "strlwr(string_array)".

printf("the lower case of the given string is '%s'\n",a );

This is also the line replacing the loop in the first program. The symbol "%s" is used to print the string array upto its null character. Hence the problem is solved and 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)

Converting lower case letters to upper case letter in C programming