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i, Vii ne, , Ww INPUT AND OUTPUT, , Ld) mex, , You already know that input is the data which is provided to the program through any input, device. Similarly, output is the result that is provided to the user through the output devices., , C programming language contains a set of built-in functions to read input in a program and, provide data. Also, to use these functions, C program has to call their respective header files., Following three files are automatically opened when aC program executes:, , ©) stdin for standard input from the keyboard, ®) stdout for the standard output to the monitor, ©) stderr for standard error to be displayed on the screen., , , , printf() and scanf() functions., , The statement #include <stdio.h> tells the C compiler's preprocessor to include the stdio.h, standard header file in the source code. This header file contains the declarations of standard, input-output functions, such as scanf and printf., , printf(), , printf() is a function which is used to print on the screen. It is used to display the output in the, form of text, numbers and the values of the variables. Remember, a text string is always, enclosed in double quotes (““), like the statement given below:, , printf(“Let us learnC”);, , The above code snippet, after compilation and execution, will display the following output:, LetuslearnC, , However, special format specifiers are needed to display integers, long integers, float values, etc. Format specifiers are special character sequences that are prefixed with % character., These are used to specify different types of value. Commonly used format specifiers in the, printf statement are as follows:, , , , , , , , , , , , %d for an integer, %ld for a long integer, %c for a character, %s for a string, , fF for a float value, %% for a single %, , , , , , , , , , ——— |
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Let us consider a few example statements:, printf(“%d”, 100);, , printf(“%f", 3.14);, , printf(“%c”, '2');, , printf(“%s”, “C language”);, , printf(“%d %f”, 100, 2.3);, , printf(“%d”, 999*10);, , printf () also allows to display string and values., for example:, , printf(“The value of pi is %f”, 3.14);, , The output of the above statement will be as follows:, The value of pi is 3.14, , ESCAPE SEQUENCES, , When a character is preceded by a backslash (\), then it is called an escape sequence and has, special meaning to the compiler., , Below, is an example of how an escape sequence appears in a program and then, how it is, , displayed to the user., ————————— oe, , Hello\nThisis an example of escape sequence., , The above example of an escape sequence would display the text as follows., , Hello, , This is an example of escape sequence., , Following table shows the escape sequences available in C programming language:, , , , , , , , , , , , , , , , , , , , , , , , \t Inserts tab in the text at this point., , \b Inserts a backspace in the text at this point., , \n Inserts a newline in the text at this point., , \r Inserts a carriage return in the text at this point., , \f Inserts a form feed in the text at this point., , ¥ Inserts a single quote character in the text at this point., Y Inserts a double quote character in the text at this point., \\ Inserts a backslash character in the text at this point., , , , HI oes ws crt ant cur |
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scanf(), , The scanf statement helps the user to provide input to a C program at the runtime. This input, value is stored into a variable of respective data type. For example, to store an integer in a, variable, the statement will be as follows:, , scanf(“%d”, &num);, , A variation of scanf statement allows you to accept multiple inputs in variables. Look at the, following statement:, , scanf(“%d %F %d”, Sx, &y, &z);, , In the above statement, the first value entered will be stored in variable x, second in variable y, and third in variable z., , Let us now look at a program:, , , , , , #include<stdio.h>, #include<conio.h>, void main(), {, inta,b;, floatc;, printf(“Enter two integers and one float value :”);, scanf(“%d %d %F”, &a, &b, &c);, printf(“The two integer values are %d and %d”, a, b);, printf(“\nThe float value is %f”, c);, getch();
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/* Program to accept three integers and display them in same line*/, , #include<stdio.h>, , #include<conio.h>, , void main(), , {, int x, y, Z;, printf("Enter three numbers : ");, scanf("%d %d %d", &x, &y, &z);, printf("\nDisplaying values in same line : \n");, printf("x=%d y=%d z=%d", x, y, z);, getch();, , , , , , , , , , , , , , /*Program to accept three integers and display them in separate lines*/, #include<stdio.h>, , #include<conio.h>, void main(), , {, int x, y, 2;, printf("Enter three numbers : ");, scanf("%d %d %d", &x, &y, &z);, printf("\nDisplaying values in separate lines : \n");, printf("x=%d \ny=%d \nz=%d", x, y, z);, getch();, , , , , , , , , , I ares wi crt ant cur
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getchar() and putchar() functions, , The getchar() function is used to read a single character typed into a variable. In case you want, to read more than one character typed, you can use this in a loop (explained in the successive, chapters)., , Similarly, the putchar() function is used to display a single character on the screen. In case you, want to display more than one character on the screen, you can use this in a loop (explained in, the successive chapters)., , /*Program to accept single character and display a single character*/, #include<stdio.h>, #include<conio.h>, void main(), , {, , , , char ch;, , printf("Enter a character:");, ch=getchar();, , printf("The character entered is :");, putchar(ch);, , getch();, , , , , , , , }, , , , Let us now observe another example code, where we will read and display multiple characters:, , /*program read and display multiple characters*/, , , , #include <stdio.h>, #include<conio.h>, void main(), {, int i;, int ch;, for( i = 1; I<= 5;i++), {, ch = getchar();, putchar(ch);, , }, getch();
