部分习题代码丢失，需要请联系博主。
编译环境：Visual Studio 2017
#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>
void out_add(void);
void out_sub(void);
void out_mul(void);
void out_div(void);
int main(void)
//3
{
int ch,i=0,I=0;//考虑到EOF的返回值
while ((ch=getchar())!=EOF)
{
if (islower(ch))
i++;
if (isupper(ch))
I++;
}
printf("i=%d\tI=%d", i, I);
system("pause");
return 0;
}
//4
{
int ch;//考虑到EOF的返回值
float i = 0, I = 0;
while ((ch=getchar())!=EOF)
{
if (isalpha(ch))
i++;
if (isblank(ch))
I++;
}
printf("x=%f",i/(I+1));
system("pause");
return 0;
}
//5 二分法
{
int i = 50, upper = 100, lower = 0;
printf("50?\n");
while (getchar()!= 'y')
{
printf("Tell me big or small:\n");
while (getchar() != '\n')
continue;
if (getchar() == 's')
{
lower = i;
i = (i+upper)/2;
printf("%d?", i);
while (getchar() != '\n')
continue;
}
else
{
upper = i;
i = (i + lower) / 2;
printf("%d?",i);
while (getchar() != '\n')
continue;
}
}
system("pause");
return 0;
}
//此处遇到一个问题：
{
int i = 50, upper = 100, lower = 0;
printf("50?\n");
while (getchar() != 'y')
{
printf("Tell me big or small:\n");
while (getchar() != '\n')
continue;
if (getchar() == 'a')
{
i = 1;
printf("%d?", i);
while (getchar() != '\n')
continue;
}
if (getchar() == 'b')
{
i = 2;
printf("%d?", i);
while (getchar() != '\n')
continue;
}
//6
{
int i = 1;
char ch;
while(i)
while ((ch = getchar()) != '\n' && (ch!= '\t') && (ch != ' '))
{
putchar(ch);
i = 0;
break;
}
system("pause");
return 0;
}
//8
{
char choice;
printf("Enter the operation of your choice:\n");
printf("a. add\ts. subtract\n");
printf("m. multiply\td. divide\n");
printf("q. quit\n");
while ((choice=getchar())!='q')
{
switch (choice)
{
case 'a':out_add();
break;
case 's':out_sub();
break;
case 'm':out_mul();
break;
case 'd':out_div();
break;
default:
break;
}
while ((getchar() != '\n'))
continue;
printf("Enter the operation of your choice:\n");
printf("a. add\ts. subtract\n");
printf("m. multiply\td. divide\n");
printf("q. quit\n");
}
system("pause");
return 0;
}
void out_add(void)
{
float x, y, z;
printf("Enter the first number:\n");
if (scanf("%f", &x) != 1)
printf("%s is not a number,try again!\n",x);
printf("Enter the second number:\n");
if (scanf("%f", &y) != 1)
printf("%s is not a number,try again!\n", y);
z = x + y;
printf("%f+%f=%f\n", x, y, z);
}
void out_sub(void)
{
float x, y, z;
printf("Enter the first number:\n");
if (scanf("%f", &x) != 1)
printf("%s is not a number,try again!\n", x);
printf("Enter the second number:\n");
if (scanf("%f", &y) != 1)
printf("%s is not a number,try again!\n", y);
z = x - y;
printf("%f-%f=%f\n", x, y, z);
}
void out_mul(void)
{
float x, y, z;
printf("Enter the first number:\n");
if (scanf("%f", &x) != 1)
printf("%s is not a number,try again!\n", x);
printf("Enter the second number:\n");
if (scanf("%f", &y) != 1)
printf("%s is not a number,try again!\n", y);
z = x * y;
printf("%f*%f=%f\n", x, y, z);
}
void out_div(void)
{
float x, y, z;
printf("Enter the first number:\n");
while (scanf("%f", &x) != 1)
printf("%s is not a number,try again!\n", x);
printf("Enter the second number:\n");
while (scanf("%f", &y) != 1)
printf("%s is not a number,try again!\n", y);
while (y == 0)
{
printf("y cannot = 0,try again!\n");
while (scanf("%f", &y) != 1)
printf("%s is not a number,try again!\n", y);
}
z = x / y;
printf("%f/%f=%f\n", x, y, z);
}