C语言编程学习课件 (15).pdf
Programming In CProgramming In C Programming In CProgramming In C Practical softwares usually need to provide human-computer interaction.For example,to log in the mailbox and Facebook,you need to enter the username and password.C also has no input statements,but calls standard library functions to receive data input from keyboard.scanfscanf()()getchargetchar()()getchgetch()()gets()gets()Programming In CProgramming In C printf()corresponds to the scanf()function,which is used to input the data from the keyboard according to the set format.getchar()corresponds to putchar()and inputs one character from the keyboard.gtes()corresponds to puts()and receives several characters input from the keyboard until the enter key is pressed.Programming In CProgramming In C The prototype for scanf()is int scanf(const char*control_string,.);As can be seen from the syntax format and function of scanf(),it must have at least 2 parameters.The first is a format-control string enclosed in double quotations,specifying the type and format of input data.The second parameter tells the system where the received data is loaded into memory.scanf()functions format specifiers(1)Code Meaning%a Reads a floating-point value(C99 only).%c Reads a single character.%d Reads a decimal integer.%i Reads an integer in either decimal,octal,or hexadecimal format.%e Reads a floating-point number.%f Reads a floating-point number.scanf()functions format specifiers(2)Code Meaning%g Reads a floating-point number.%o Reads an octal number.%s Reads a string.%x Reads a hexadecimal number.%p Reads a pointer.%n Receives an integer value equal to the number of characters read so far.%u Reads an unsigned decimal integer.Programming In CProgramming In C#include stdio.h void main()int a;char c;float b,x;printf(Enter a,b,c:);scanf(%d%f,%c,&a,&b,&c);x=a*a+b*c;printf(x=%.3fn,x);Program output Enter a,b,c:x=262.500 Programming In CProgramming In C#include stdio.h void main()int a;short b;float c;double x;scanf(a,b:%4d%2hd,&a,&b);scanf(%5f,%*d,%6lf,&c,&x);printf(a=%d,b=%hdn,a,b);printf(c=%f,x=%lfn,c,x);Program output a=5432,b=56 c=2.567000,x=90.313000 a,b:543256 2.567,67,90.313 Programming In CProgramming In C#include stdio.h void main()char ch1,ch2;scanf(%c,&ch1);scanf(%c,&ch2);printf(%d%dn,ch1,ch2);Program output B A 65 66 fflush(stdin);fflush(stdin);getchar()It has no parameters and returns one character input from the keyboard.When executing,it will read a character from the input buffer.If the buffer is empty,it will wait for the input from keyboard.Press Enter to end the input.The last Enter key will remain in the buffer.getchar()#include stdio.h void main()char sex,sp;sex=getchar();fflush(stdin);fflush(stdin);scanf(%c,&sp);getchar();getchar();printf(“sex=%c,sp=%cn,sex,sp);output M K or any key sex=M,sp=K getch()needs to include the header file“conio.h”.getch()output getch()#include stdio.h#include conio.h void main()char ch1,ch2,ch3;printf(Enter Password：);ch1=getch();putchar(*);ch2=getch();putchar(*);ch3=getch();putchar(*);getch();printf(nPassword：%c%c%c,ch1,ch2,ch3);getch();Enter Password：*Password：abc The gets()function receives a string input from the keyboard and ends with Enter key.The last Enter key will not remain in the buffer.gets()can receive the string with blank spaces.gets(String address)gets()scanf()ends with a blank space,TAB,or Enter key.And the Enter key will be residual scanf(“%s“,String address)Programming In CProgramming In C
