C语言程序设计教程课后习题参考答案

《C语言程序设计教程》课后习题参考答案

习题11.（1）编译、链接 .exe（2）函数 主函数（或main函数）（3）编辑编译链接2.

（1）-（5）：DDBBC（6）-（10）：ABBBC3.

（1）答：C语言简洁、紧凑，使用方便、灵活；C语言是高级语言，同时具备了低级语言的特征；C语言是结构化程序设计语言，具有结构化的程序控制语句；C语言有各种各样的数据类型；C语言可移植性好；生成目标代码质量高，程序执行效率高。（2）编辑、编译、链接、执行（3）一个C程序由一或多个函数组成，一函数若干条语句构成，每条语句的末尾必须以分号结束。（4）标识符，关键字，运算符，分隔符，常量，注释符等4. 从键盘输入一个双精度小数，打印出它的余弦值。#include #include main( ){double x;scanf(“%lf”, &x);printf(“%lfn”, cos(x) );}第2章1.（1）BDE、ACFG（2）D(3)C(4)C2．(1)错（2）错（3）错（4）对（5）错3.

（1）a=3,b=-27（2）a=11,b=6,c=6（3）3（4）10101（5）-998（6）1）202）83）704.（1）#include main( ){14）005）06）0

double r, h ,v;r = 2.5;h = 3.5;v = 3.14*r*r*h;printf(“v=%lfn”, v);}(2)#include main( ){char ch;ch = getchar( );printf(“%cn”, ch + 32);}(3)#include main( ){printf(“ *n”);printf(“ ***n”);printf(“ *****n”);printf(“*******n”);}(4)#include main( ){double x;scanf(“%lf”, &x);printf(“%d , %lfn”, (int)x, x – (int)x );}(5)#include main( ){double a=3, b=5;double result = (-2 * a + ( 4*a – b )/( 2*a + b ) )/( (a - 4*b)/(a + b) );printf(“%lfn”, result);}

习题31.（1）D(2)AD(3)C(4)B(5)A(6)-(10):BDACB2.(1)3.141593,3.1416,3.142(2)c=K(3)| 123.46|,|123 |(4)x= 1.23,y= 50.00(5)03.(1)scanf(%f”, c); 改为：scanf(“%f”, &c);f = (9/5)*c+32;改为：f = (9.0/5)*c + 32;printf(“摄氏温度%f度相当于华氏温度%f度”, &c, &f); 改为：printf(“摄氏温度%f度相当于华氏温度%f度”, c, f);(2)补充定义:int h;h = 500/60改为: h = 500 / 60;m = 500% 60 改为： m = 500%60;printf(“500分钟是%d小时%d分钟,”&h, &m); 改为：printf(“500分钟是%d小时%d分钟” , h, m);4.（1）#includemain( ){char x,y;scanf(“%c%c”, &x, &y);printf(“%dn”, (x-‘0’) + (y-‘0’) );}（2）#include main( ){char x, y;char tmp;printf(“Input two characters:”);scanf(“%c%c”, &x, &y);printf(“Before swap: x=%c, y=%cn”, x, y);

tmp = x;x = y;y = tmp;printf(“After swap: x=%c, y=%cn”, x, y);}(3)#include main( ){char ch;ch = getchar( );printf(“%cn”, ch - 32);}第4章1.（1）-（5）：CAACA2.(1)BBB(2)AAABBBCCC(3)end(4)d=20(5)s=2,t=3(6)first third(7)y=0y=5y=10y=53.(1)y=’A’ && ch<=’Z’ch>=’a’&&ch<=’z’ch = ch-32(3)x>2&&x<=10x>-1&&x<=2(4)t=x;x=y;y=t;4.(1)#include main( ){int x, y , z, t;scanf(“%d%d%d”, &x, &y, &z);if ( x>y ){ t=x; x=y; y=t;}if( x > z )

{t = x; x = z; z= t; }if( y > z ){t = y; y= z; z = t;}printf(“%d %d %dn”, x, y ,z);}(2)#include main( ){int score;scanf(“%d”, &score);if ( score < 0 || score > 100 )printf(“成绩不合理n”);else if( score>=90 )printf(“优秀n”);else if( score>=80 )printf(“良好n”);else if( score >= 70 )printf(“中等n”);else if( score >= 60 )printf(“及格n”);elseprintf(“不及格n”);}(3)#include main( ){int n;int g,s,b,q;//各位上的数值scanf(“%d”, &n);g = n%10;//个位s = n/10%10;//十位b = n/100%10;//百位q = n/1000%10;//千位if( n < 10 ) //一位数{printf(“%dn”, 1);//位数printf(“%dn”, g); //各位上的数值}else if ( n < 100 ) //两位数{printf(“%dn”, 2);//位数printf(“%d %dn”, g,s);

}else if ( n < 1000 ) //三位数{printf(“%dn”, 3);//位数printf(“%d %d %dn”, g, s, b);}else if ( n < 10000 ) //四位数{printf(“%dn”, 4);//位数printf(“%d %d %d %dn”, g, s, b, q);}}(4)#include main( ){int n;scanf(“%d”, &n);if( n % 3==0 && n%5==0 && n%7==0 )printf(“能同时被3、5、7整除n”);else if( n%3==0 && n%5==0)printf(“能被3和5整除n”);else if( n%3==0 && n%7==0 )printf(“能被3和7整除n”);else if( n%5==0 && n%7==0 )printf(“能被5和7整除n”);else if( n%3==0 || n%5==0 || n%7==0 ){if( n%3==0 )printf(“能被3整除n”);else if( n%5==0 )printf(“能被5整除n”);elseprintf(“能被7整除n”);}elseprintf(“不能被3、5、7中任一个数整除n”);}(5)#include main( ){int carType;//车型。1代表夏利；2代表富康；3代表桑塔纳double xiali = 2.1;//每公里价格

double fukang = 2.4;double sangtana = 2.7;double distance; //距离double totalMoney;//总的收费printf("请输入您乘坐的车型：1代表夏利；2代表富康；3代表桑塔纳：");scanf("%d", &carType);printf("请输入您乘车的总路程：");scanf("%lf", &distance);if( carType == 1)//夏利{if( distance < 3 )totalMoney = 7.0;elsetotalMoney = 7 + xiali * (distance – 3);}else if( carType == 2 ) //富康{if( distance < 3 )totalMoney = 8.0;elsetotalMoney = 8 + fukang * (distance – 3);}else if( carType == 3 ) //富康{if( distance < 3 )totalMoney = 9.0;elsetotalMoney = 9 + sangtana * (distance – 3);}printf("（四舍五入）您的车费为：%.0lfn", totalMoney );}(6)#include main( ){double a, b, c;scanf(“%lf%lf%lf”, &a, &b, &c);if( a+b>c && b+c>a && c+a>b ){if( a==b && b==c )printf(“等边三角形n”);else if( a==b || b== c || c==a )printf(“等腰三角形n”);

elseprintf(“一般三角形n”);}elseprintf(“不能构成三角形n”);}第5章1.(1)C(2)C(3)K=36(4)C(5)B2.(1) 3次(2) x>=1 && x<=10 || x>=200&&x<210(3) e == 0(4) 6次(5) 103.(1) 20,10(2) 16,0(3) 7BAB4BAB1BC(4) ABABABC(5) ************ ****** ******4.(1) a != b(2) n / 10(3) scanf(“%d”, &a);5. (3) 行int fac = 1, sum = 0;6.(1)#include main( ){char ch;

int alpha=0, space=0, digit=0, other=0;while( (ch=getchar( ) ) != ‘n’ ){if( ch>=’A’&&ch<=’Z’ || ch>=’a’&&ch<=’z’)alpha++;else if( ch>=’0’ && ch<=’9’)digit++;else if( ‘ ‘ == ch )space++;elseother++;}printf(“%d %d %d %dn”, alpha, digit, space, other );}(2)#include main( ){int m20, m10;for(m20=1; m20<5; m20++){for(m10 = 1; m10<10; m10++)if( 20*m20+10*m10 == 100 )printf(“%d, %dn”, m20, m10 );}}(3)#include main( ){int x, y, z;for(x=0; x<10; x++)for(y=0; y<10; y++)for(z=0; z<10; z++)if( x*100+y*10+z + y*100+z*10+z == 532 )printf(“%d %d %dn”, x, y, z);}(4)#include main( ){int row, spaceCount,starCount;int n;scanf("%d", &n);

for( row = 1; row <= n; ++row){for( spaceCount = 1;spaceCount <= n - row ;++ spaceCount)printf(" "); //打印出某行上星号前的空格for( starCount = 1;starCount <= 2* row - 1;++starCount )printf("*"); //打印出某行上的所有星号printf("n"); //换行}//打印下半部分for(row=1; rowmain( ){int n;int g,s,b,q;int t;scanf("%d", &n);g = n % 10;s = n / 10 % 10;b = n /100 % 10;q = n/ 1000%10;g = (g+5)%10;s = (s+5)%10;b = (b+5)%10;q = (q+5)%10;//第1位和第4位交换t = g; g = q; q = t;//第2位和第3位交换

t = s; s = b; b = t;printf("%d%d%d%dn", q,b,s,g);}第6章1.

（1）无返回值（2）double2（3）无限循环（死循环）（4）result = 7202.（1）#include void print1( int n );main( ){int n;scanf("%d", &n);print1( n );}void print1( int n ){int row, col;for(row = 1; row<=n; row++){for(col=1; col<=row; col++)printf("#");printf("n");}}（2）#include void print2( int n );main( ){int n;

scanf("%d", &n);print2( n );}void print2( int n ){int row, col;for(row = 1; row<=n; row++){for(col=1; col<=2*row-1; col++)printf("@");printf("n");}}（3）#include int yearOld(int byear, int bmonth, int bday, int nyear, int nmonth, int nday);main( ){int nowy,nowm,nowd;int by, bm, bd;int age;printf("请输入生日:");scanf("%d%d%d", &by, &bm, &bd);printf("请输入现在日期:");scanf("%d%d%d", &nowy, &nowm, &nowd);age= yearOld(by,bm,bd,nowy,nowm,nowd);printf("age=%dn", age);}int yearOld(int byear, int bmonth, int bday, int nyear, int nmonth, int nday){int age;age = nyear - byear;if( nmonthbday)age--;return age;}（4）#include int sum( int n );main( )

{int n,s;scanf("%d", &n);s = sum( n );printf("s=%dn", s);}int sum( int n ){int s=0;while ( n ){s += n % 10;n /= 10;}return s;}（5）#include double sumfac( int n );main( ){int n;scanf("%d", &n);printf("%.0lfn", sumfac( n ) );}double sumfac( int n ){double f=1.0, s = 0.0;int i;for(i=1;i<=n; i++){f *= i;s += f;}return f;}（6）#include int gcd(int m , int n);main( )

{int m, n;scanf("%d%d", &m, &n);printf("%dn", gcd(m ,n) );}int gcd(int m, int n){int t,r;if( m < n ){ t = m; m= n; n = t; }r = m % n;while( r ){m = n;

n = r;r = m % n;}return n;}（7）#include int gcd(int m , int n);int lcm(int m, int n);main( ){int m, n;scanf("%d%d", &m, &n);printf("%dn", lcm(m ,n) );}int gcd(int m, int n){int t,r;if( m < n ){ t = m; m= n; n = t; }r = m % n;while( r ){m = n;

n = r;r = m % n;}

return n;}int lcm(int m, int n){return m*n/gcd(m,n);}（8）#include double mypower(double x, int y);main( ){double x;

int y;scanf("%lf%d", &x, &y);printf("%lfn", mypower(x,y) );}double mypower(double x, int y){int i;double f=1.0;for(i=1; i<=y; i++)f *= x;return f;}第7章1.（1）6（2）5（3）不能（4）int a[3][2]={{1,2}, {3,4}, {5,6} };（5）69（6）abcG2.（1）#include void reverse( int a[ ], int n );int main( ){

int array[10]={0};int i;printf(“请输入10个整数：”);for( i=0; i<10; i++)scanf(“%d”, &array[i]);reverse( array, 10); //调用函数逆序存储数组中的数据printf(“逆序后的元素为：n”);for( i=0; i<10; i++)printf(“%5d”, array[i]);printf(“n”);return 0;}void reverse( int a[ ], int n ){int i;int tmp;for( i=0;i#include void reverseStr( char str[ ] );main( ){char s[100];gets( s );reverseStr( s );puts( s );}void reverseStr( char str[ ] ){int i,j;char t;i=0;j=strlen(str)-1;while( i < j ){t = str[i];a[n-i-1] = tmp;

str[i] = str[j];str[j] = t;i++;j--;}}（3）#include int copyTo(int s1[], int n, int s2[ ]);main( ){int s1[10], s2[10];int i,count;for(i=0; i<10; i++)scanf("%d", &s1[i]);count = copyTo(s1, 10, s2);for(i=0; ivoid copyToStr(char str1[ ], char str2[ ] );main( ){char s1[100], s2[100];gets(s1);copyToStr( s1, s2 );puts(s2);}void copyToStr(char str1[ ], char str2[ ] )

{int i=0,j=0;while( str1[i] != '0' ){if( str1[i]>='a'&&str1[i]<='z' ){str2[j] = str1[i];j++;}i++;}str2[j] = '0';return j;}（5）#include void deleteAll( char str[ ], char ch);main( ){char s[100], ch;gets( s );ch = getchar( );deleteAll( s, ch );puts( s );}void deleteAll( char str[ ], char ch){int i, j;i = 0;

j = 0;while( str[i] ){if( str[i] != ch ){str[j++] = str[i];}i++;}str[j] = '0';}（6）#include

void replaceAll(char str[ ], int ch1, char ch2);main( ){char s[100], c1, c2;gets( s );c1 = getchar( );c2 = getchar( );replaceAll( s, c1, c2 );puts( s );}void replaceAll(char str[ ], int ch1, char ch2){int i;i = 0;while( str[i] ){if( str[i] == ch1 )str[i] = ch2;i++;}}（7）#include int transformToBin( int dnum, int bin[ ] ) ;int main( ){int array[32]={0}; //保存转换后的二进制数int num; //待转换的整数int cc;//最后得到的二进制总共多少位printf(“请输入一个整数：”);scanf(“%d”, &num);cc = transformToBin( num, array ); //调用转换函数cc--; //往回退一个元素下标，使cc指向最后一个元素for( ; cc>=0;cc-- ) //输出转换后的二进制数printf(“%d”, array[cc]);printf(“n”);return 0;}int transformToBin( int dnum, int bin[ ] ){

int count = 0;while ( dnum ) //当dnum还未转换完毕

{bin[count++] = dnum % 2;//余数保留到数组对应元素中dnum /= 2;//数本身除2}return count;}（8）#include int transformToHex( int dnum, char hex[ ] ) ;int main( ){char array[32]; //保存转换后的进制数int num; //待转换的整数int cc;//最后得到的进制总共多少位printf("请输入一个整数：");scanf("%d", &num);cc = transformToHex( num, array ); //调用转换函数cc--; //往回退一个元素下标，使cc指向最后一个元素for( ; cc>=0;cc-- ) //输出转换后的进制数printf("%c", array[cc]);printf("n");return 0;}int transformToHex( int dnum, char hex[ ] ){int count = 0;int t;while ( dnum ) //当dnum还未转换完毕

{t = dnum % 16;if( t < 10 )hex[count] = t+'0';//余数保留到数组对应元素中else

hex[count] = t-10+'A';count++;dnum /= 16;//数本身除16}return count;}

（9）#include #include #include #define M 5 //行#define N 6 //列void generate( int a[ ][N], int row, int col );void display( int a[][N], int row, int col);void getMaxEveryRow(int a[][N], int row, int col, int y[]);main( ){int arr[M][N], y[M]={0};int i;generate(arr, M, N);display(arr, M, N);getMaxEveryRow(arr,M,N,y);//输出最大值for(i=0; i

{y[i] = a[i][0];for(j=1; j#include #include #define M 5 //行#define N 6 //列void generate( int a[ ][N], int row, int col );void display( int a[][N], int row, int col);void getMinEveryCol(int a[][N], int row, int col);main( ){int arr[M][N];int i;generate(arr, M, N);display(arr, M, N);getMinEveryCol(arr,M,N);//输出最小值for(i=0; i

printf("%4d", a[i][j]);printf("n");}}void getMinEveryCol(int a[][N], int row, int col){int i,j;for(i=0; i a[j][i] )a[0][i] = a[j][i];}}第8章1.

（1）局部（2）void（3）auto（4）auto（5）return（6）递归（7）求 1!+2!+3!+4!+5!（8）注意全局变量和局部变量的区别2.（1）#include #include double xc( double x, double y );main( ){double a, b;double c;scanf(“%lf%lf”, &a, &b);c = xc( a, b );printf(“ %lfn”, c);}double xc( double x, double y ){return sqrt( x*x+y*y );}（2）staticexternregister

#include long seconds(int hour, int minute, int second);main( ){int h,m,s;long sec;printf("输入时间:");scanf("%d%d%d", &h, &m, &s);sec = seconds(h,m,s);printf("离12点最近的秒数：%ldn", sec);}long seconds(int hour, int minute, int second){long s;if( hour < 6 ){s = second+minute*60+hour*60*60;}else{s = 60-second+(60-minute-1)*60+(12-hour-1)*60*60;}return s;}（3）#include int fun( int n );main( ){int n;scanf("%d", &n);if( fun( n ) ) //是质数，则输出该数；不是的话，不作任何处理printf("%dn", n );}int fun( int n ){int i;for(i=2; i

return 1;}（4）#include int fun( int n );main( ){int n;int count=0;for(n=2;n<1000;n++)if( fun( n ) )

{printf("%4d", n );count++;if( count % 10 == 0 )printf("n");}printf("n");}int fun( int n ){int i;for(i=2; iint func( int n );main( ){int n;scanf("%d", &n);printf("%dn", func(n) );}int func( int n ){if ( 1 == n )

return 3;return 2*func(n-1)-1;}（6）#include int gcd(int m, int n);main( ){int x,y,t;scanf("%d%d", &x, &y);if( x < y ){t=x; x=y; y=t;}printf("%dn", gcd(x,y) );}int gcd(int m, int n){if (0==n)return m;return gcd(n, m%n);}第9章1.（1）xyzNKT（2）bcdefgh（3）4，4（4）qponmzyx（5）abcCD（6）02．（1）#include #include void reverse( int *p, int n);main( ){int i;int a[10]={1,2,3,4,5,6,7,8,9,10};

reverse(a,10);

for(i=0; i<10; i++)printf("%d ", a[i]);printf("n");}void reverse( int *p, int n){int *q;int t;q = p + n - 1;while( p < q ){t = *p;

*p = *q;*q = t;p++;q--;}}（2）#include #include void reverseStr( char *str );main( ){char s[100];gets(s);reverseStr(s);puts(s);}void reverseStr( char *str ){char *pEnd,t;pEnd = str + strlen(str) - 1;while( str < pEnd ){t = *str;*str = *pEnd;*pEnd = t;str++;pEnd--;}}

（3）#include int copyTo(int *s1, int n, int *s2);main( ){int a[10]={1,2,3,4,5,6,7,8,9, 10};int b[10], count,i;count=copyTo(a,10,b);for(i=0; ivoid copyToStr(char *str1, char *str2);main( ){char s1[100], s2[100];gets( s1 );copyToStr(s1, s2);puts( s2 );}void copyToStr(char *str1, char *str2){while( *str1 ){if( *str1 >= 'a' && *str1 <= 'z' ){*str2++=*str1;

}str1++;}*str2 = '0';}（5）#include void deleteAll(char *str, char ch);main( ){char s[100], c;gets(s);c = getchar( );deleteAll(s, c);puts(s);}void deleteAll(char *str, char ch){char *p;p = str;while( *str ){if( *str != ch )*p++ = *str;str++;}*p = '0';}（6）#include void replaceAll( char *str, char ch1, char ch2);main( ){char s[100], c1, c2;printf("输入字符串:");gets(s);printf("输入查找字符：");c1 = getchar( );fflush(stdin); //清除键盘缓冲区printf("输入替换字符：");c2 = getchar( );replaceAll(s,c1, c2);

puts(s);}void replaceAll( char *str, char ch1, char ch2){while( *str ){if( *str == ch1 ){*str = ch2;}str++;}}（7）#include int transformToBin( int dnum, int *bin ) ;int main( ){int array[32]; //保存转换后的进制数int num; //待转换的整数int cc;//最后得到的进制总共多少位printf("请输入一个整数：");scanf("%d", &num);cc=transformToBin( num, array ); //调用转换函数cc--; //使cc指向最后一个元素for( ; cc>=0;cc-- ) //输出转换后的进制数printf("%d", array[cc]);printf("n");return 0;}int transformToBin( int dnum, int *bin ){int *pb;int t;pb = bin;while ( dnum ) //当dnum还未转换完毕

{t = dnum % 2;*pb = t;pb++;dnum /= 2;//数本身除2}

return pb-bin;}（8）#include #include void transformToHex( int dnum, char *hex ) ;int main( ){char array[32]; //保存转换后的进制数int num; //待转换的整数int cc;//最后得到的进制总共多少位printf("请输入一个整数：");scanf("%d", &num);transformToHex( num, array ); //调用转换函数cc=strlen(array)-1; //使cc指向最后一个元素for( ; cc>=0;cc-- ) //输出转换后的进制数printf("%c", array[cc]);printf("n");return 0;}void transformToHex( int dnum, char *hex ){char *ph;int t;ph = hex;while ( dnum ) //当dnum还未转换完毕

{t = dnum % 16;if( t < 10 )*ph = t+'0';else

*ph = t-10+'A';ph++;dnum /= 16;//数本身除16}*ph = '0';}（9）#include void strToLow(char *str);main( )

{char s[100];gets( s );strToLow( s );puts( s );}void strToLow( char *str ){while( *str ){if( *str>='A'&&*str<='Z' )*str = *str + 32;str++;}}第10章1.（1）12（2）(++p)->num（5）B（6）B2.（1）struct myDate{int year, month, day;};（2）struct empInfo{char empNo[15];char empName[10];char xb; //性别int age;struct myDate empDay;double salary;};（3）#include typedef struct STUDENT {char name[20];float height;3）D7）10，A4） p2 != NULL（（（

int score;}STUD;main( ){STUD a;printf(“姓名：”);gets( );printf(“身高:”);scanf(“%f”, &);printf(“成绩:”);scanf(“%d”, &);//输出信息（仅为测试用）printf(“%s %.2f %d n”, , , );}第11章1.（1）打开文件：fopen 关闭文件：fclose使用：FILE *fp;fp = fopen(“myfile”, “r”);…fclose( fp );（2）”w”（3）文本文件：内容均以字符的形式存储，占的字节数可能会大些 二进制文件：内容以二进制编码的形式存储，占的字节数可能会稍小。（4）第一个参数：读取得到的信息存储在内存的哪个地方 第二个参数：读取的字节数 第三个参数：读取的块数 第四个参数：文件指针，表示从哪个文件中读取数据（5）第一个参数：待写入文件的信息存储在内存的哪个地方 第二个参数：写入的字节数 第三个参数：写入的块数 第四个参数：文件指针，表示要写入到哪个文件中

（6）为了安全，gets少用，因为其没有指定输入字符的大小，限制输入缓冲区得大小，如果输入的字符大于定义的数组长度，会发生内存越界，堆栈溢出。后果非常怕怕fgets会指定大小，如果超出数组大小，会自动根据定义数组的长度截断。2.（1）#include #include main( ){FILE *fpr, *fpw;char ch;fpr = fopen("", "r");fpw = fopen("", "a");if( NULL==fpr ){printf("文件打开不成功n");return 0;}if( NULL == fpw ){printf("文件打开不成功n");return 0;}while( !feof( fpr ) ){ch = fgetc( fpr );fprintf(fpw, "%c", ch);}fclose( fpr );fclose( fpw );}（2）#include main( ){FILE *fp1, *fp2;

double pi = 3.1415926;fp1 = fopen( "", "w");//以文本的形式写入fp2 = fopen( "", "wb");//以二进制的形式写入if( NULL==fp1 ){printf("文件打开不成功n");return 0;}if( NULL == fp2 ){printf("文件打开不成功n");return 0;}fprintf(fp1, "%lf", pi);fwrite(&pi,sizeof(pi),1,fp2);fclose( fp1 );fclose( fp2 );}打开之后的效果：

（3）#include #include main( ){FILE *fpr;fpr = fopen( "", "r");if( NULL==fpr ){printf("文件打开不成功n");return 0;}while( !feof( fpr ) ){

putchar( fgetc( fpr ) );}fclose( fpr );}（4）#include typedef struct STUDENT {char no[15];char name[10];int score;}STUD;#define N 3main( ){STUD s[N];int i;FILE *fp;int count; //读取文件时才使用for(i=0; i

count = 0;while( !feof( fp ) ){if( fread(&s[count], sizeof(s[count]), 1, fp) )count++;}fclose(fp);//输出for(i=0; i