codelab

There are a number of different C input commands, the most useful of which is the scanf command. To read a single integer value into the variable called a you can use: scanf("%d",&a); When the program reaches the scanf statement it pauses to give the user time to type something on the keyboard and continues only when users press Enter or Return, to signal that he, or she, has finished entering the value. Then the program continues with the new value stored in a. In this way, each time the program is run the user gets a chance to type in a different value to the variable and the program also gets the chance to produce a different result! The final missing piece in the jigsaw is using the printf function, the one we use to print the value currently being stored in a variable. To display the value stored in the variable a you can use: printf("The value stored in a is %d",a); Note: the scanf function does not prompt for an input. You should ge...

A variable is just a named area of storage that can hold a single value (numeric or character). C is very fussy about how you create variables and what you store in them. It demands that you declare the name of each variable that you are going to use and its type, or class, before you actually try to do anything with it. There are five basic data types associated with variables: int - integer: a whole number. float - floating point value: i.e. a number with a fractional part. double - a double-precision floating point value. char - a single character. void - valueless special purpose type. One of the confusing things about the C language is that the range of values and the amount of storage that each of these types takes is not defined. This is because in each case the 'natural' choice is made for each type of machine. You can call variables what you like, although it helps if you give them sensible names that give you a hint of what they're being u...