C语言上机练习参考答案

n 第1章 C语言概述1-1 编写程序，在屏幕上显示一个如下输出： - Programming in C is fun! I love C language.-Program#include main()printf(-n); printf(Programming in C is fun!n); printf(I love C language.n);printf(-n);1-2 编写程序，在屏幕上显示一个如下图案： * * * * * * * * * *Program (1)#include main()printf(* * * *n); printf( * * *n);printf( * *n);printf( *n );Program (2) #include main()printf(%c%4c%4c%4cn, *, *, *, *); printf(%3c%4c%4cn, *, *, *);printf(%5c%4cn, *, *);printf(%7cn , *);1-3 已知某个圆的半径，编写一个程序，用来计算并显示面积。要求：将定义为符号常量，并假设一个恰当的半径值。Program#include #define PI 3.14main()float r=5, s;s = PI*r*r; printf(The area of circle is: %.2fn, s);Output The area of circle is: 78.501-4 已知两个整数20和10，编写程序，自定义函数add( )将这两个数相加，自定义函数sub( )计算这两个数的差，并按照下面形式显示计算结果：20+10=30 20-10=10Program#include int add(int a, int b)return (a+b);int sub(int a, int b)return (a-b);main()int a=20, b=10;printf(%d + %d = %dn, a, b, add(a, b);printf(%d - %d = %dn, a, b, sub(a, b);Output 20 + 10 = 3020 10 = 101-5 已知变量a、b和c的值，编写程序，用来计算并显示x的值，其中请分别用以下数值运行该程序（1）a=250，b=85，c=25（2）a=300，b=70，c=80Program (1)#include main()int a=250, b=85, c=25;float x;x=1.0*a/(b-c);printf(x = %.2fn, x);Output (1)x = 4.17Program (2)#include main()int a=300, b=70, c=80;float x;x=1.0*a/(b-c); /*试写成x=a/(b-c); 得到什么运行结果？为什么？*/printf(x = %.2fn, x);Output (2)x = -30.00n 第2章 常量、变量及数据类型 & 第3章 运算符和表达式3-1 编写程序，求华氏温度100oF对应的摄氏温度。计算公式如下：式中：c表示摄氏温度，f表示华氏温度。（c定义为实型，f定义为整型）Program #include main()int f=100;float c;c=5.0*(f-32)/9;/*如果是c=5*(f-32)/9; 会是什么结果？为什么？*/printf(Celsius degree (corresponding to %d Fahrenheit) is: %.2f.n, f, c);Output Celsius degree (corresponding to 100 Fahrenheit) is: 37.78.3-2 一个物体从100m的高空自由落下，编写程序，求它在前3s内下落的垂直距离。设重力加速度为10m/s2。要求，将重力加速度定义为符号常量，尝试将其改为9.8 m/s2，看结果有何不同？Program #include #define G 10main()int t=3;float s;s=1.0/2*G*t*t; /*如果是s=1/2*G*t*t; 会是什么结果？为什么？*/printf(The falling vertical distance (in %d seconds) is: %.2f.n, t, s);Output The falling vertical distance (in 3 seconds) is:45.00.3-3 将球的半径R定义为符号常量，计算球的表面积（4R2）和体积（4/3*R3）。Program #include #define R 5.2#define PI 3.14main()float s, v;s=4*PI*R*R;v=4.0/3*PI*R*R*R;printf(The surface area of the ball (radius is %.2f) is: %.2f, and the volume is: %.2f.n, R, s, v);Output The surface area of the ball (radius is 5.20) is: 339.62, and the volume 588.68.3-4 给定x、y和z的值，编写程序，使x等于y的值，y等于z的值，z等于x的值。Program #include main()int x=1, y=2, z=3, t;printf(Before swap: x=%d, y=%d, z=%d.n, x, y, z);t=x;x=y;y=z;z=t;/*变量t的作用是什么？*/printf(After swap: x=%d, y=%d, z=%d.n, x, y, z);Output Before swap: x=1, y=2, z=3.After swap: x=2, y=3, z=1.3-5 编写一个程序，给定一个浮点数（例如456.78），显示该数的十位数字与个位数字之和（例如5+6=11）。Program (1)#include main()float f=456.78;int n, a, b;n=f;a = n%10;/*赋值后，a是什么值？*/b = n/10%10;/*赋值后，b是什么值？*/printf(The sum of the tens digit and units digit of %.2f is: %d + %d = %d.n, f, b, a, a+b);Program (2)#include main()float f=456.78;int n, a, b;n=f;a = n%10;b = n%100/10;/*该语句与上面程序不同，看看有何区别？*/printf(The sum of the tens digit and units digit of %.2f is: %d + %d = %d.n, f, b, a, a+b);Output The sum of the tens digit and units digit of 456.78 is: 5+ 6 = 11.3-6 某种物品每年折旧费的计算方法如下：编写一个程序，当给定某物品的购买价格、使用年限和每年的折旧费时，计算出其废品价值。Program #include main()float price=120.65, year=3, depreciation=10.2, value;value = price - year*depreciation;printf(The scrap value is %.2f.n, value);Output The scrap value is 90.05.3-7 在库存管理中，某单个物品的经济定购数EOQ由下面等式给定：而最优的定购时间间隔TBO由下面等式给定：编写程序，给定需求率（单位时间内的物品数）、生产成本（每个定购）和储备成本（单位时间内每种物品），计算EOQ和TBO。Program #include #include main()int demand=1000;float product_cost=3.5, storage_cost=0.63, eoq, tbo;eoq=sqrt(2*demand*product_cost/storage_cost);tbo=sqrt(2*product_cost/demand/storage_cost);printf(EOQ is %.2f, and TBO is %.2f.n, eoq, tbo); Output EOQ is 105.41, and TBO is 0.11.n 第4章 输入输出操作管理4-1 输入两个数，将它们交换后输出。Program #include main()int x, y, t;printf(Please input 2 numbers: );scanf(%d%d, &x, &y);printf(Before swap, the 2 numbers are: %d, %dn, x, y);t=x;x=y;y=t;printf(After swap, the 2 numbers are: %d, %dn, x, y);Output Please input 2 numbers: 3 5/* Blue is input */Before swap, the 2 numbers are: 3, 5After swap, the 2 numbers are: 5, 34-2 输入一个十进制数，输出对应的八进制数和十六进制数。Program #include main()int n;printf(Please input a decimal number: );scanf(%d , &n);printf(The octal is %o, and the hexadecimal is %x.n, n, n);Output Please input a decimal number: 10/* Blue is input */The octal is 12, and the hexadecimal is a.考虑：如何得到下面的输出？Please input a decimal number: 10/* Blue is input */The octal is 012, and the hexadecimal is 0xa.4-3 编写程序，输入3个整数，计算并输出它们的平均值。Program #include main()int a, b, c;printf(Please input 3 integers: );scanf(%d%d%d, &a, &b, &c);printf(The average is %.2f.n, (a+b+c)/3.0);Output Please input 3 integers: 4 7 -19/* Blue is input */The average is -2.67.4-4 编写一个程序，读取x和y的值，显示下面表达式的值：（1）（2）（3）Program #include main()float x, y;printf(Please input x and y: );scanf(%f%f, &x, &y);printf(1) (x+y)/(x-y) = %.2fn, (x+y)/(x-y);printf(2) (x+y)/2 = %.2fn, (x+y)/2);printf(3) (x+y)(x-y) = %.2fn, (x+y)*(x-y);Output Please input x and y: 3.5 4.1/* Blue is input */(1) (x+y)/(x-y) = -12.67(2) (x+y)/2 = 3.80(3) (x+y)(x-y) = -4.564-5 计算银行存款的本息。编写程序，输入存款金额money、存期year和年利率rate，根据下列公式计算存款到期时的本息合计sum（税前），输出时保留两位小数。Program #include #include main()float money, rate, sum;int year;printf(Please input the deposit money: );scanf(%f, &money);printf(Please input the deposit period: );scanf(%d, &year);printf(Please input the annual interest rate: );scanf(%f, &rate);sum=money*pow(1+rate, year);printf(The total principal and interest is: %.2fn, sum);Output Please input the deposit money: 2500/* Blue is input */Please input the deposit period: 3/* Blue is input */Please input the annual interest rate: 0.023/* Blue is input */The total principal and interest is: 2676.504-6 输入圆柱的高h和半径r，求圆柱体积volume=*r2*h。Program #include #define PI 3.14main()float volume, r, h;printf(Please input the radius of the cylinder: );scanf(%f, &r);printf(Please input the height of the cylinder: );scanf(%f, &h);volume=PI*r*r*h;printf(The volume of the cylinder is: %.2fn, volume);Output Please input the radius of the cylinder: 3.5/* Blue is input */Please input the height of the cylinder: 12.7/* Blue is input */The volume of the cylinder is: 488.514-7 编写一个程序，读取一个实数f，将其四舍五入的值赋值给整型变量n，输出n的值。（尝试不用if语句完成本程序，并考虑负数是否适用）Program (1)#include main()float f;int n, m;printf(Please input a real number: );scanf(%f, &f);m=f*10;m=m%10/5;/*m是什么值？*/n=f;n=n+m;/*m有何作用？*/printf(The rounded integer is: %dn, n);Program (2)如果不明白if语句，可以在学完第5章后再看。#include main()float f;int n, m;printf(Please input a real number: );scanf(%f, &f);n=f+0.5;/*是否理解该语句？*/printf(The rounded integer is: %dn, n);Output (1)Please input a real number: 3.6/* Blue is input */The rounded integer is: 4Output (2)Please input a real number: -13.2/* Blue is input */The rounded integer is: -134-8 编写程序，读入两个两位数字的整数，并按照如下形式输出这两个整数的乘积。4 5* 3 7 3 1 51 3 5 1 6 6 5提示：注意格式！Program #include main()int x, y, m, n;printf(Please input 2 integers: );scanf(%d%d, &x, &y);printf(%5dn *%3dn-n, x, y);m=y%10;n=y/10;printf(%5dn%4dn-n%5dn, x*m, x*n, x*y);n 第5章 判断与分支5-1 输入一个字符ch，根据不同情况进行输出：（1）ch为小写字母，输出对应的大写字母；（2）ch为大写字母，按照原样输出；（3）ch为数字，输出对应的数字；（4）ch为其他字符，输出“Other character.”。Program #include main()char ch;printf(Please input a character: );ch=getchar();if (ch=a & ch=A & ch=0 & ch=9)printf(%dn, ch-0);elseprintf(Other character.n);Output (1)Please input a character: A/* Blue is input */AOutput (2)Please input a character: b/* Blue is input */BOutput (3)Please input a character: 3/* Blue is input */3Output (4)Please input a character: /* Blue is input */Other character.5-2 为鼓励居民节约用水，自来水公司采用按月用水量分段计费的办法，居民应交水费y元与月用水量x吨的函数关系式如下（设x0）。编写程序，输入用户的月用水量x吨，计算并输出该用户应支付的水费y元（保留两位小数）。Program #include main()float x, y;printf(Please input the water consumption: );scanf(%f, &x);if(x=15)y=4*x/3;/*是否可以写成y=4/3*x;？区别在哪里？*/elsey=2.5*x-10.5;printf(The water price is: %.2f. n, y);Output Please input the water consumption: 27.9/* Blue is input */The water price is: 59.255-3 输入一个年份year，判断year是否为闰年。year若为闰年，需要满足下列条件之一：（1）能被4整除，但不能被100整除（如2004年是闰年，2100年不是闰年）（2）能被400整除（如2000年是闰年）Program #include main()int year;printf(Please input the year: );scanf(%d, &year);if (year%4=0&year%100!=0)|(year%400=0)printf(%d is a leap year!n, year);elseprintf (%d is not a leap year!n, year);Output Please input the year: 1900/* Blue is input */1900 is not a leap year!5-4 输入3个实数，将其按照降序输出（较大数在前），保留3位小数。Program (1)#include main()float x, y, z;printf(Please input 3 real numbers: );scanf(%f%f%f, &x, &y, &z);if (xy)if(yz)printf(%.3f, %.3f, %.3fn, x, y, z);elseif(xz)printf(%.3f, %.3f, %.3fn, x, z, y);elseprintf(%.3f, %.3f, %.3fn, z, x, y); elseif(xz)printf(%.3f, %.3f, %.3f, y, x, z);elseif(yz)printf(%.3f, %.3f, %.3fn, y, z, x);elseprintf(%.3f, %.3f, %.3fn, z, y, x);/*程序结束时，x, y, z的值是否发生了变化？*/Program (2)#include main()float x, y, z,t;printf(Please input 3 real numbers: );scanf(%f%f%f, &x, &y, &z);if (xy)t=x; x=y; y=t;if (xz)t=x; x=z; z=t;if (yz)t=y; y=z; z=t;/*此程序与上面的程序有何不同？*/printf(%.3f, %.3f, %.3fn, x, y, z); /*程序结束时，x, y, z的值是否发生了变化？*/Output Please input 3 real numbers: 7.8 5 10/* Blue is input */10.000, 7.800, 5.0005-5 输入五级制成绩（AE），输出相应的百分制成绩（0100）区间。五级制成绩对应百分制程序区间为：A（90100）、B（8089）、C（7079）、D（6069）和E（059）。例如：输入B，输出（8089）。（1）用switch语句实现；（2）用if语句实现。Program (1)#include main()char grade;printf(Please input the grade: );scanf(%c, &grade);switch (grade)case A: printf(90100n);break;case B: printf(8089n);break;case C: printf(7079n);break;case D: printf(6069n);break;case E: printf(059n);break;default:printf(Wrong grade! n);Program (2)#include main()char grade;printf(Please input the grade: );scanf(%c, &grade);if (grade=A)printf(90100n);else if (grade=B)printf(8089n);else if (grade=C)printf(7079n);else if (grade=D)printf(6069n);else if (grade=E)printf(059n);elseprintf(Wrong grade! n);Output Please input the grade: B/* Blue is input */80895-6 用switch语句实现，输入数字17，输出对应的英文单词Monday, Tuesday, , Sunday。Program #include main()int day;printf(Please input the day in a week: );scanf(%d, &day);switch(day)case 1: printf(Mondayn); break;case 2: printf(Tuesdayn);break;case 3: printf(Wednesdayn);break;case 4: printf(Thursdayn); break;case 5: printf(Fridayn); break;case 6: printf(Saturdayn);break;case 7: printf(Sundayn); break;default: printf(Wrong day! n);Output Please input the day in a week: 4/* Blue is input */Thursday5-7 某高校的某专业录取研究生的条件如下：（1）英语成绩55（2）政治成绩60（3）专业课成绩60（4）以上三科的总数学成绩200，或英语和专业课的总成绩130。编写程序，读入一个学生的成绩（英语、政治和专业课），判断是否可以被录取。Program #include main()float english, politics, professional;printf(Please input score of English: );scanf(%f, &english);printf(Please input score of Politics: );scanf(%f, &politics);printf(Please input score of the professional course: );scanf(%f, &professional);if(english=55 & politics=60 & professional=60 & (english+politics+professional=200 | english+professional=130)printf(Congratulations! You have been admitted! n);elseprintf(Sorry, you have been rejected! n);Output Please input score of English: 60/* Blue is input */Please input score of Politics: 70/* Blue is input */Please input score of professional course: 60/* Blue is input */Sorry, you have been rejected!5-8 编写程序，计算下面二元方程的实数根。应用如下规则：（1）如果a和b的值为零，则没有解；（2）如果a的值为零，则只有一个解（x=-c/b）;（3）如果b2-4ac为负数，则没有实数根；（4）否则，有两个实数根：输入a, b和c的值，输出求根的情况，如有实数根，则输出实数根的值。Program #include #include main ( ) float a, b, c, f;printf ( Please input the value of a, b and c in the quadratic equation:nax*x + bx + c = 0n );printf ( a = );scanf ( %f, &a );printf ( b = );scanf ( %f, &b );printf ( c = );scanf ( %f, &c );printf ( About %.2fx*x + %.2fx + %.2f = 0: , a, b, c );if ( a = 0 & b = 0 ) printf(There is no solution!n);elseif ( a = 0 ) printf(There is only one root: %.2f.n,- c/b);elsef = b * b - 4 * a * c;if ( f 0 ) printf(There are no real root!n);elseprintf(There are 2 real roots: %.2f, %.2f.n,(-b + sqrt(f)/2/a, (-b - sqrt(f)/2/a );Output Please input the value of a, b and c in the quadratic equation:ax*x + bx + c = 0a = -3/* Blue is input */b = 4/* Blue is input */c = 5/* Blue is input */About -3.00x*x + 4.00x+5.00 = 0: There are 2 real roots: -0.79, 2.12.5-9 编写程序，读取x的值，求下面函数的值（1）用else if语句实现（2）用嵌套if语句实现（3）用条件运算符 ? : 实现Program (1)#include main ( )float x;printf ( Please input the value of x: );scanf ( %f, &x );if ( x 0 )printf ( y = 1n );elseif ( x = 0 ) printf ( y = 0n );elseprintf ( y = -1n );Program (2)#include main ( )float x;printf ( Please input the value of x: );scanf ( %f, &x );if ( x != 0 )/*写成if(x)是否正确？*/if ( x 0 )/*写成if(x)是否正确？*/printf ( y = 1n );elseprintf ( y = -1n );elseprintf ( y = 0n );Program (3)#include main ( )float x;printf ( Please input the value of x: );scanf ( %f, &x );printf ( y = %dn, x 0 ? 1 : x 0 ? -1 : 0 );Output Please input the value of x: 9/* Blue is input */y = 15-10 某个服装展示厅宣布以下所卖物品季节性打折：购买总额折扣机加工制品手工制品0100无折扣5%1012005%7.5%2013007.5%10.0%大于30010.0%15.0%编写程序，计算某顾客应付的款项。要求：同时用switch和if语句实现。Program #include main ( )float price, discount;char category;printf ( Category (m/h): ); scanf ( %c, &category );printf ( Price: ); scanf ( %f, &price );if ( category = m )switch ( (int) (price-1)/100 )case 0:discount = 0;break;case 1:discount = 0.05;break;case 2: discount = 0.075; break;default:discount = 0.1; else switch ( (int) (price-1)/100 )case 0:discount = 0.05; break;case 1:discount = 0.075; break;case 2:discount = 0.1; break;default:discount = 0.15;printf (The net amount to be paid is %.2fn, price*(1-discount);Output Category (m/h): h/* Blue is input */Price: 250.60/* Blue is input */The net amount to be paid is 225.545-11 编写程序，输入x，计算并输出下列分段函数f(x)的值（保留2位小数）。提示：请调用sqrt( )函数求平方根，调用pow( )函数求幂。Program #include #include main()float x, y;printf(Please input the value of x: );scanf(%f, &x);if(x0)y=pow(x,5)+2*x+1/x;elsey=sqrt(x); printf(The value of y is: %.2f. n, y);Output Please input the value of x: -2/* Blue is input */The value of y is: -36.505-12 编写程序，输入一个实数（例如456.78），求不小于该数的最小整数和不大于该数的最大整数。（提示：注意负数）。 Program #include main()float f;int n;printf(Please input a real number: );scanf(%f, &f);n=f;if(f=0)printf(The largest integer (not larger than %.2f) is: %dn, f, n);if (f-n0)printf(The smallest integer (not less than %.2f) is: %dn, f, n+1); elseprintf(The smallest integer (not less than %.2f) is: %dn, f, n); elseif (f-n0)printf(The la