C language--introduction History 1970: b by Ken Thompson at at&t bell Lab

C language--Introduction

History

• 1970: B by Ken Thompson at AT&T Bell Lab

• 1972: C by Dennis Ritchie and Ken Tompson at At&T Bell Lab for UNIX

• 1978: “The C Programming Language” by Brian Kernighan and Dennis Ritchie (K&R C)

• 1988: ANSI C

The First Program

• #include

• main( ) { printf(“Hello, World!\n"); }

How to use printf()

• printf("Hello");

• printf("Hello\n");

• printf("%d", b);

• printf("The temperature is "); printf("%d", b); printf(" degrees\n");

• printf("The temperature is %d degrees\n", b);

• printf("%d + %d = %d\n", a, b, c);

How to use printf()

• int (integer values) uses %d

• float (floating point values) uses %f

• char (single character values) uses %c

• character strings (arrays of characters, discussed later) use %s

How to use scanf()

• scanf("%d", &b);

• int uses %d
• float uses %f
• char uses %c
• character strings use %s

• scanf("%d %d",&a, &b);