循环可以用while,do,for,goto语句表述

    while (condition) statement;

    do statement while(condition);

    for (for-init-statement; condition; expression) statement;

    goto identifier;

     identifier: statement;

while语句代码段

int a = 0; while( a > 0 ) {
       a--; }

do语句代码段

int a = 0; do {
       a--; } while( a > 0 );

for语句代码段

int sum = 0; int i; for( i=1; i <= 100;i++) {
       sum += i; }

goto语句

int i, j; for ( i = 0; i < 10; i++ ) {
       printf( "Outer loop executing. i = %d\n", i ); for ( j = 0; j < 2; j++ )     {
           printf( " Inner loop executing. j = %d\n", j ); if ( i == 3 ) goto stop;     } } // This message does not print: printf( "Loop exited. i = %d\n", i ); stop: printf( "Jumped to stop. i = %d\n", i );