C Language Basics 1

C Language Basics 1

Four elements of a function: name, input, output, processing.

source file (extension. cpp)

(The comment is behind the double slash)

Grammatical features:

Most of the code is written in curly braces {}.

The end of the sentence is usually terminated with a semicolon.

Sensitive to case

Attention:

Quotation marks, semicolons, commas, etc. must be written in the English state.

Chinese is written in double brackets only.

Function:

1, the first line of the format #include<stdio.h>

#include <stdio.h>

Include includes

Stdio Composition:

STD STANDDRD Standard

I input inputs

o outpput Output

. h Head Header file

2, the second line of the format void main ()

void Main ()

void null value, no return value

Main fixed, name

Attention:

Parentheses are not limited, there are no semicolons after parentheses

3, printf ("");

1) Print output, only content in parentheses

Example: printf ("Please enter your age");

2) Output value

Example: int n=5;

printf ("You are%d years old next year", N);

Where%d is a bitwise OR placeholder

int is an integer data type

4, scanf ("",);

int n;

scanf ("%d", &n)

Where%d is the input format

& is take address symbol

Attention:

scanf ("",) do not write in quotation marks, generally write only the placeholder.

Cases:

#include <stdio.h>//standard input output head means to include a header file of a marked//quasi-input to the program. The main function, void is to represent no//any return value, main is the name of the main function, the main function is the entry of the program, there is only//has a

void Main ()

{

Print using printf (""); semicolon end

printf ("Hello world!");

int n;//defines a variable with an integer type of int type n,n can temporarily store integer data with//

scanf ("%d", &n);

printf ("%d", &n);

}

#include <stdio.h>

void Main ()

{

int n=5, m=10;

printf ("The forest lived%d dwarfs," N);

printf ("One day, there are%d Snow White in the Forest", m);

n=7;

M=1;

printf ("The forest lived%d dwarfs," N);

printf ("One day, there are%d Snow White in the Forest", m);

}

#include <stdio.h>

void Main ()

{

int n,m,x;

printf ("Please enter your age, your father's age");

scanf ("%d%d", &n,&m);

X=m-n;

printf ("Your father is%d years older than you", x);

}

#include <stdio.h>

void Main ()

{

int n;

printf ("Please enter your age");

scanf ("%d", &n);

n=n+1;

printf ("You are%d years old next year", N);

}

#include <stdio.h>

void Main ()

{

int a,b,c;

printf ("Please enter your age");

scanf ("%d", &a);

printf ("Please enter your father's age");

scanf ("%d", &b);

printf ("Your Age is%d", a);

printf ("Your father's age is%d", b);

C=b-a;

printf ("Your father is%d years older than you", c);

}

#include <stdio.h>

void Main ()

{

int a,b,c,s,x,y;

printf ("Pool radius, square radius");

scanf ("%d%d", &a,&b);

C=6*a;

S=3*b*b-3*a*a;

X=10*c;

y=50*s;

printf ("Pool fence length%d", c);

printf ("Square area%d", s);

printf ("Pool fence cost%d", x);

printf ("Square Tile cost%d", y);

}

Data type

(1) Int integer type

(2) Double decimal

(3) Float decimal, single-precision floating-point number

(4) Char character type

Char s[]= "Hello"

Defines a person with a length of string, in square brackets to write a number greater than the length of a character in quotation marks.

printf ("%lf", b) LF is 6 digits after the decimal point

printf ("%s", B) s is a string

printf ("%c", B) c is a single character

Double is twice times the number of flout digits.

C Language Basics 1