<08> While loop introduction and basic format +while loop using traps + statistics keyboard input characters +

While loop introduction and basic Format (master):
   Loop structure:          when the conditions are met, the program repeats the conditions that make up the    loop          structure of a piece of code:1) cyclic          control conditions 2  ) Loop body           3) Let the loop control condition be false to control the format of the while    loop         :while(expression) {                        statement block;        

1#include <stdio.h>2 3 voidtest1 () {4 5     intI=1;6     7     //1) Cyclic control conditions8      while(i<= +){9         Ten         //2) Circulation body Oneprintf"%d Times said: I love you!\n", i); A          -         //allows the loop control condition to be false -i = i+1; the          -     } -  -  + } -  + voidtest2 () { A  at     //calculate the 1+2+3+.....+100 and -     //defines a variable that stores the number of times the current period is executed -     intI=1, sum=0; -     intn=0; -     //Suppose you enter a number from the keyboard to calculate the 1+2+3+....+n and -printf"Please enter a number: \ n"); in     //accept a number from a keyboard -scanf"%d",&n); to      +      while(i<=N) { -          the         //value +i with the value of sum *sum = sum+i;//i = 1 sum = 1 $         //0+1, (0+1) +2Panax Notoginseng          -         //let the loop condition be false control the         //i=i+1; +i++; A     } the      +printf"1+2+3+....+%d=%d\n", n,sum); -  $ } $  - intMainintargcConst Char*argv[]) { -      the test1 (); -     Wuyi      the     return 0; -}

While loops use traps:

There is no statement that allows the loop control condition to be false

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Count the number of characters entered by the keyboard:

1#include <stdio.h>2 3 intMainintargcConst Char*argv[]) {4     5     //Defining Variables6     intCount=0;//used as a counter7     Charch;8     9     Ten     //Accept Characters Onescanf"%c",&ch); A      -     //Loops -      while(ch!='\ n') { the         //Calculator +1 -count++; -         //continue to remove one character -         //the scanf principle, if the buffer is not empty, will not let the user enter the content again, +         //and continue to get it directly from the buffer. -scanf"%c",&ch); //Quite brilliant thought, while constant judgment, equivalent to the outer multi-scanf statement only executes once  +     } A      atprintf"count =%d\n", count); -      -      -     return 0; -}

<08> While loop introduction and basic format +while loop using traps + statistics keyboard input characters +