42C语言课后答案--谭浩强 清华大学出版社

第一章1.3写出一个C程序的构成。一个C程序可以由若干个源程序文件（分别进行编译的文件模块）组成，一个源文件可以由若干个函数和预处理命令以及全局变量声明部分组成，一个函数由数据声明部分和执行语句组成。1.5#includestdio.hvoidmain(){printf(********************);printf(\n);printf(VeryGood!);printf(\n);printf(********************);scanf(%d);}1.6编写一个C程序，输入a,b,c三个值，输出其中最大值。#includestdio.hvoidmain(){inta,b,c,max;scanf(%d,%d,%d,&a,&b,&c);if(ab){max=b;b=a;a=max;}if(ac){max=c;c=a;a=max;}printf(%d\n,a);}第三章3.5字符常量和字符串常量有什么区别？答：字符常量是一个字符，在程序中字符是用单引号括起来的。字符串常量有0个或若干个字符组合而成，在程序中字符串是用双引号括起来的，在储存时系统自动在字符串最后面加一个结束符号’\0’。3.6写出下列程序的运行结果：aa︼bb︼︼︼cc︼︼︼︼︼︼abc︼︼︼︼︼︼︼A︼N3.7#includestdio.hvoidmain(){charc1,c2,c3,c4,c5;c1='C';c2='h';c3='i';c4='n';c5='a';c1=c1+4;c2=c2+4;c3=c3+4;c4=c4+4;c5=c5+4;printf(%c%c%c%c%c,c1,c2,c3,c4,c5);}3.9求下面算术表达式的值。（1）2.5（2）3.53.109,11,9,103.12（1）24（2）10（3）60（4）0（5）0（6）0第四章4.4#includestdio.hvoidmain(){inta,b,c;floatx,y,z;longu,n;charc1,c2;a=3;b=4;c=5;x=1.2;y=2.4;z=-3.6;u=51274;n=128765;c1='a';c2='b';printf(a=%2db=%2dc=%2d\n,a,b,c);printf(x=%8.6f,y=%8.6f,z=%9.6f\n,x,y,z);printf(x+y=%5.2fy+z=%5.2fz+x=%5.2f\n,x+y,y+z,z+x);printf(u=%6ldn=%9ld\n,u,n);printf(c1='%c'or%d(ASCII)\n,c1,c1);printf(c2='%c'or%d(ASCII)\n,c2-32,c2);}4.5请写出程序的输出结果：575767.856400,-789.12402367.856400,-789.12402367.86,-789.12,67.856400,-789.124023,67.856400,-789.1240236.785640e+01,-7.89e+02A,65,101,411234567,4553207,d68765533,177777,ffff,-1COMPUTER,COM4.6a=3︼b=7︼8.5︼71.82︼A︼a4.7︼︼︼10︼︼︼20Aa1.5︼-3.75︼1︼67.84.8#includestdio.hvoidmain(){floatr,h,a,b,c,d,e;floatp=3.141592653;scanf(r=%fh=%f,&r,&h);a=2*p*r;b=p*r*r;c=4*p*r*r;d=(3.0/4.0)*p*r*r*r;e=p*r*r*h;printf(yuanzhouchang:a=%.2f\n,a);printf(yuanmianji:b=%.2f\n,b);printf(yuanqiubiaomianji:c=%.2f\n,c);printf(yuanqiutiji:d=%.2f\n,d);printf(yuanzhutiji:e=%.2f\n,e);}4.10(1)#includestdio.hvoidmain(){charc1,c2;printf(pleaseprintc1,c2:);c1=getchar();c2=getchar();printf(useputchartoprinttheresult:);putchar(c1);putchar(c2);printf(\n);printf(useprintfprinttheresult:);printf(%c%c\n,c1,c2);}c1和c2可以定义为字符型或整型，二者皆可。(2)要使程序结果输出c1和c2的ASCII码，要在printf函数中用%d格式符输出，即：printf(%d%d\n,c1,c2);(3)字符变量在计算机内占用一个字节，而整型变量占用两个字节。因此整型变量在可输出字符的范围内（ASCII码为0~255之间的字符）是可以与字符数据互相转换的。如果整数在此范围外，则不能替代。第五章习题5.3#includestdio.hvoidmain(){inta,b,c,x,y;a=3;b=4;c=5;printf(%d\n,a+bc&&b==c);printf(%d\n,a||b+c&&b-c);printf(%d\n,!(ab)&&!c||1);printf(%d\n,!(x=a)&&(y=b)&&0);printf(%d\n,!(a+b)+c-1&&b+c/2);}5.4#includestdio.hvoidmain(){inta,b,c;scanf(%d,%d,%d,&a,&b,&c);if(ab)if(bc)printf(max=%d\n,c);elseprintf(max=%d\n,b);elseif(ac)printf(max=%d\n,c);elseprintf(max=%d\n,a);}5.5#includestdio.hvoidmain(){intx,y;scanf(%d,&x);if(x1)y=x;elseif(x=10)y=3*x-11;elsey=2*x-1;printf(x=%d,y=%d\n,x,y);}5.6#includestdio.hvoidmain(){floatscore;chargrade;printf(student'sscoreis:);scanf(%f,&score);switch((int)(score/10)){case10:case9:grade='A';break;case8:grade='B';break;case7:grade='C';break;case6:grade='D';break;default:grade='E';}printf(gradeis%c\n,grade);}5.9#includestdio.hvoidmain(){inta,b,c,d,t;printf(pleaseprintfournumbers:);scanf(%d%d%d%d,&a,&b,&c,&d);if(ab){t=a;a=b;b=t;}if(ac){t=a;a=c;c=t;}if(ad){t=a;a=d;d=t;}if(bc){t=b;b=c;c=t;}if(bd){t=b;b=d;d=t;}if(cd){t=c;c=d;d=t;}printf(theorderis:%d%d%d%d\n,a,b,c,d);}第六章习题6.1#includestdio.hvoidmain(){intm,n,t,s,i;scanf(m=%dn=%d,&m,&n);if(mn){t=m;m=n;n=t;}s=m*n;while(m!=0){i=n%m;n=m;m=i;}printf(highestcommondivissor=%d\n,n);printf(leastcommonmultiple=%d\n,s/n);}6.4#includestdio.hvoidmain(){intn;floats,i;s=0;i=1;for(n=1;n=20;n++){i=i*n;s=s+i;}printf(%.1f\n,s);}6.6#includestdio.hvoidmain(){intn,a,b,c;for(n=100;n1000;n++){a=n/100;b=n/10-a*10;c=n%10;if(n==a*a*a+b*b*b+c*c*c)printf(%d,n);}printf(\n);}6.8#includestdio.hvoidmain(){inti,t;floata,b,c;a=1;b=2;c=0;for(i=1;i=20;i++){c=c+b/a;t=b;b=a+b;a=t;}printf(%f\n,c);}6.11#includestdio.h#includemath.hvoidmain(){floata,x0,x1;printf(thenumberis:);scanf(%f,&a);x0=a;x1=(x0+a/x0)/2;while(fabs(x0-x1)=1e-5){x0=x1;x1=(x0+a/x0)/2;}printf(thesquarerootof%.0fis:%f\n,a,x1);}6.14#includestdio.hvoidmain(){inti,j,n;for(i=0;i=3;i++){for(j=0;j=2-i;j++)printf();for(n=0;n=2*i;n++)printf(*);printf(\n);}for(i=0;i=2;i++){for(j=0;j=i;j++)printf();for(n=0;n=4-2*i;n++)printf(*);printf(\n);}}第七章习题7.2#includestdio.hvoidmain(){inti,j,min,t,a[11];for(i=1;i=10;i++){printf(a[%d]=,i);scanf(%d,&a[i]);}printf(\n);for(i=1;i=10;i++)printf(%5d,a[i]);printf(\n);for(i=1;i=9;i++){min=i;for(j=i+1;j=10;j++)if(a[min]a[j])min=j;t=a[i];a[i]=a[min];a[min]=t;}printf(\nThesortednumbers:\n);for(i=1;i=10;i++)printf(%5d,a[i]);}7.4#includestdio.hvoidmain(){inta[5]={2,4,6,8};intnum,i,j;printf(arraya:\n);for(i=0;i4;i++)printf(%5d,a[i]);printf(\n);printf(enterdatais:);scanf(%d,&num);if(numa[3])a[4]=num;else{for(i=0;i4;i++)if(a[i]num){for(j=3;j=i;j--)a[j+1]=a[j];a[i]=num;break;}}printf(newarraya:\n);for(i=0;i5;i++)printf(%5d,a[i]);printf(\n);}7.5#includestdio.hvoidmain(){inti,j,a[5];printf(enterarraya:\n);for(i=0;i5;i++)scanf(%d,&a[i]);printf(arraya:\n);for(i=0;i5;i++)printf(%5d,a[i]);printf(\n);for(i=0;i5/2;i++){j=a[i];a[i]=a[4-i];a[4-i]=j;}printf(newarra