Input and output formats summary

C language

• scanfIn addition to %coutside input to other formats is a symbol of white space (spaces, TAB, Enter) marks the end

• Therefore, scanfunless %cthe character is read by a space, otherwise the space will be skipped

• %c You can receive a space, tab, carriage return

• Use string %sread in, is a space and line feed as read into the end marker

• Use getchar, putcharinput and output of a single character

  • getcharCan recognize line breaks, so when the knockout round if the latter have getcharwill be put into your account

• 2#3This input format, do not forget the scanfinside to keep this format

• getsAn input line of the string, putsto the output string, and a line feed plus

  • If getsthere's still a scanfOr cin, remember to use getcharabsorption

• Utility output format

  //%md  超过或等于m位保持原样，不足m位，高位用空格补齐
  printf("%5d");
  //%0md  超过或等于m位保持原样，不足m位，高位用0补齐!!!!!!非常好用
  printf("%05d");
  //%.mf  保留m位小数输出
  printf("%.5f");

  C++

• Control output bits

#include<iomanip> //控制时要加入这个头文件
cout << setiosflags(ios::fixed)<<setprecision(2)<<123.4567<<endl;//控制输出位数

• stringOnly with cin,coutinput and output
• 2#3 This input format may be a char additional variable, cin >> ch absorb it
• getline Whole line for inputting a character string
  • If getlinethere's still a scanfOr cin, remember to use getcharabsorption

//string类型
string str;
getline(cin, str);
//char *类型
char s[20];
cin.getline(s, 20);

• Used map, the character string to integer mapping muststring

Case

//输入格式：字符串1 字符串2 字符串3 ...数量未知
//输入格式：数字1 数字2 数字3 ...
//这种限于后面没有其他输入了
//这也是输入多组数据，组数未知的方式
while(scanf("%s")!=EOF){
    
}

/*
输入格式：
123 [数字]
aa bb cc [是一个整体的字符串]
字符串1 字符串2 字符串3 ... [组数未知的多组字符串]
1998 [数字]
*/
//c++
cin>>id;
getchar();  //注意！！
getline(cin,str1);
while(cin>>str2){
    ...
    char ch = getchar();
    if(ch == '\n') break; //注意！！
}
cin>>num;
//c语言
scanf("%d",&n);
getchar(); //注意！！
gets(str);
while(scanf("%s",str2)!=EOF){
    ...
    char ch = getchar();
    if(ch == '\n') break;
}
scanf("%d",&num);