C-language loop structure

Loop structure:

1.goto Unconditional Transfer Statement

goto//Unconditional Transfer Statement////label://goto Label;//goto Union if statement use//try not to use goto//only within the current function to jump int main (int argc, const char * argv[]) { C0/>int i=0;print://    printf ("Hello world\n");    i++;    if (i<10) {        goto print;    }        return 0;}

Example: Goto implementation 1-100 Add

#include <stdio.h>int main (int argc,const char *argv[]) {    int sum=0;    int I=1;label:    sum+=i;    i++;    if (i<=100) {        goto label;    }    printf ("sum =%d\n", sum);    return 0;}

2.while Cycle Structure

While//while (expression)//{//    loop body Statement list,//}//expression true, execution loop body, false exit Loop # include <stdio.h>int main (int argc,const char * Argv[]) {    int i=1;    int sum = 0;    while (i<=100) {        sum+=i;        i++;    }    printf ("sum =%d\n", sum);        return 0;}

Example: Statistics input a line of characters from the keyboard

Method One:

int main (int argc,const char *argv[]) {    int cnt=0;//statistic count    Char ch;    while (scanf ("%c", &ch), ch!= ' \ n ') {//stdin        cnt++;    }    printf ("cnt =%d\n", cnt);        return 0;}

Method Two:

int main (int argc,const char *argv[]) {    int cnt=0;    while (GetChar ()! = ' \ n ') {//getchar reads a character from the standard input file each time and returns the character to        cnt++;    }    printf ("cnt =%d\n", cnt);//stdout standard output file    fprintf (stdout, "cnt =%d\n", cnt);        return 0;}

3.do...while

do//{//    loop body;//}//while (conditional expression);//execute the Loop body first, and then determine whether the expression is set up//1-100 odd and (do While) int main (int argc, const char *ARGV []) {    int sum =0;    int i=1;    Do    {        if (i%2)        {            sum + = i;        }        i++;    }    while (i<=100);    printf ("sum =%d\n", sum);    return 0;}

4. For loop structure

For//for (Assignment statement; conditional expression; Change statement) {//    loop body;//}int Main (int argc,const char *argv[]) {    int i;        for (i = 0; i<10; i++) {        printf ("Hello world\n");    }    return 0;}

Example: printing all odd numbers within 1-100 (for implementation)

int main (int argc,const char *argv[]) {    for (int i=1; i<=100; i++) {        if (i%2) {            printf ("%d", I);        }    }    printf ("\ n");    Putchar (' \ n ');//output one character        return 0;}

eg. Continue,break keyword Usage

int main (int argc,const char *argv[]) {    for (int i=0; i<10; i++) {        if (i==5) {            continue;//ends this loop, continues the next loop 
   //break;//jumps out of the whole loop        }        printf ("i =%d Hello world\n", i);    }    return 0;}

Example: Find all the primes in 1-100

All primes in 1~100/*int main (int argc,const char *argv[]) {    int i,j;    For (I=1, i<=100; i++) {for        (j=2; j<i; J + +) {//i% (2 ~ i-1)            if (i%j==0) {break                ;            }        }        if (i!=j) {            continue;        }        printf ("%d", I);    }    return 0;} */

C-language loop structure