"C-Sequence program structure"

One, c statements

Can be divided into the following five categories:

① expression Statements

An expression;

②, Function call statement

function name (actual parameter table);

③, control statements

Conditional Judgment statement: If statement, switch statement;

Loop execution statement: Do While statement, while statement, for statement;

Turn statement: Break statement, Goto statement, continue statement, return statement.

④, compound statements

A statement consisting of multiple statements enclosed in parentheses {} is called a compound statement.

⑤, empty statements

Only semicolons ";" The composed statement is called an empty statement. Empty statements are statements that do nothing. In the program Hollow statement can be used as an empty loop body

such as:while (GetChar()! ='\ n');

Function: Re-enter as long as the character entered from the keyboard is not a carriage return. The loop body here is an empty statement.

Ii. input/Output functions

scanf ("Format control string", Address table column);

The address is made up of the address operator "&" followed by the variable name.

For example: &a, &b represents the address of variable A and variable B, respectively.

printf ("Format control string", output table column);

"%d" means output by decimal integer;

"%ld" indicates the output by decimal length integer;

"%c" means output by character type and so on.

Putchar function (character output function);

Its function is to output a single character on the display. The general form is:

Putchar (character variable);

GetChar function (keyboard input function);

The function of the GetChar function is to enter a character from the keyboard. The general form is:
GetChar ();
The input character is usually given a character variable, which forms an assignment statement

Practice: To find the root of the ax2+bx+c=0 equation, a, B, C by the keyboard input, set b2-4ac>0.

2. #include <stdio.h>
   
4. #include <math.h>
   
6. int main(void){
   
8. float a, b, C, disc, X1, X2, P, Q;
   
10. scanf("a=%f,b=%f,c=%f", &a, &b, &c);
    
12. Disc=b*b-4*a*c;
    
14. P=-b/(2*a);
    
16. Q=sqrt(disc)/(2*a);
    
18. X1=p+q; X2=p-Q;
    
20. printf("x1=%.2f x2=%.2f\ n", x1, X2);
    
22. return 0;
    
24. }

"C-Sequence program structure"