I want to write a program that converts integer to another char and print them. I expect to work but It didn't work anyway even if I want to print same integer without converting.
My code is here:
#include<stdio.h>
int main()
{
FILE *fp;
int a;
fp=fopen("deneme.txt", "r");
while(feof(fp)) {
fscanf(fp,"%d",&a);
switch(a) {
case 0:
printf(" ");
break;
case 1:
printf("-");
break;
case 2:
printf("_");
break;
case 3:
printf("|");
break;
case 4:
printf("/");
break;
case 5:
printf("\\");
break;
case 6:
printf("O");
break;
default:
break;
}
}
}
My txt is that:
Related
When I enter the letter 'q' as grade, it runs infinitely.
#include <stdio.h>
#include <stdbool.h>
int main(void) {
int grade;
bool flag = true;
while (flag) {
puts("-----------------------------"); // comment
printf("What's your grade out of 10? ");
scanf(" %d", &grade);
switch (grade) {
case 10:
case 9:
case 8:
case 7:
case 6:
printf("Pass\n");
break;
case 5:
printf("Fail\n");
break;
case 4:
printf("Fail\n");
break;
case 3:
printf("Fail\n");
break;
case 2:
printf("Fail\n");
break;
case 1:
printf("Fail\n");
break;
case 0:
printf("Fail\n");
break;
default:
printf("Illegal Grade\n");
flag = false;
break;
}
}
return 0;
}
scanf(" %d",&grade);
It scans int in string. "q" is not int. When you enter "q", value of the variable grade left unchanged. You must check returned value of scanf to validate number of filled placeholders.
if (scanf(" %d",&grade) != 1) {
printf("Illegal Grade\n");
exit(1); // or break
}
Other parts are ok.
scanf(" %d", &grade); fails when you type something that cannot be parsed as into an integer. grade is not modified, so it is uninitialized if the conversion error happens immediately and the behavior is undefined, otherwise you get the same value and behavior as the previous time.
The offending input stays in the input stream, so the same thing happens when the code executes again in the while loop, hence the infinite loop.
You want to test if the conversion was successful and discard the input if not:
#include <stdio.h>
#include <stdbool.h>
int main(void) {
int res, c, grade;
bool flag = true;
while (flag) {
puts("-----------------------------"); // comment
printf("What's your grade out of 10? ");
res = scanf("%d", &grade);
if (res == EOF)
break;
if (res == 0) {
printf("Invalid input\n");
/* discard the offending line of input */
while ((c = getchar()) != EOF && c != '\n')
continue;
/* try again */
continue;
}
switch (grade) {
case 10:
case 9:
case 8:
case 7:
case 6:
printf("Pass\n");
break;
case 5:
case 4:
case 3:
case 2:
case 1:
case 0:
printf("Fail\n");
break;
default:
printf("Illegal Grade\n");
flag = false;
break;
}
}
return 0;
}
From the book "Programming in C"
Write a program that takes an integer keyed in from the terminal and extracts and displays each digit of the integer in English. So, if the user types in 932, the program should display
nine three two
Remember to display “zero” if the user types in just a 0.
Its been hours and its still cant be solved.. Do anyone know how to? This is the code so far
#include <stdio.h>
int right_digit,number;
int main ()
{
scanf("%i",&number);
right_digit = number % 10;
switch (right_digit)
{
case '0':
printf("0");
break;
case '1':
printf("one");
break;
case '2':
printf("two");
break;
case '3':
printf("three");
break;
case '4':
printf("four");
break;
case '5':
printf("five");
break;
case '6':
printf("six");
break;
case '7':
printf("seven");
break;
case '8':
printf("eight");
break;
case '9':
printf("nine");
break;
default:
break;
}
number = number / 10;
return 0;
}
The first problem here is, you're (wrongly) trying to use the character representation of the integer numbers. In your code, right_digit is supposed to represent an integer digit, not a character literal.
You must not to use the ''s, just write
case 0:
...
case 1:
and so on.
Just to add a bit on your mistake, it was considering the corresponding integer values of the character literal '0', '1' and so on. For ASCII, they are equivalent to
case 48:
case 49:
.
.
which is not what you intended.
That said,
You need to put the modulo calculation and switch-case inside a loop and carry out the conversion for all the digits of the input integer.
You need to start printing from the beginning (MSB), currently , you're printing from LSB. (Hint: Start printing the result of the modulo operation)
printf("0"); should be printf("Zero ");, as per the requirement.
/*USING SWITCH CASE ...ALSO YOU CAN USE '0' and negative numbers */
#include <stdio.h>
#include <stdlib.h>
int main (void)
{
int rem,num,sum=0,rem1,num1,add;
printf("enter the number:\n");
scanf("%i",&num);
if(num<0)
{
printf("minus ");
num=-num;
}
if(num==0)
{
printf("zero");
}
while(num!=0)
{
rem=num%10;
num=num/10;
sum=sum*10 +rem;
}
/*printf("%i\n",sum);*/
while(sum!=0)
{
rem1=sum%10;
sum=sum/10;
switch(rem1)
{
case 0:
printf("zero ");
break;
case 1:
printf("one ");
break;
case 2:
printf("two ");
break;
case 3:
printf("three ");
break;
case 4:
printf("four ");
break;
case 5:
printf("five ");
break;
case 6:
printf("six ");
break;
case 7:
printf("seven ");
break;
case 8:
printf("eight ");
break;
case 9:
printf("nine ");
break;
default:
printf("invalid no");
}
}
return 0;
}
Hope this program will help you to understand the logic and I am also posting the solution for same problem using switch case....
/* Write a program that takes an integer keyed in from
* the terminal and extracts and displays each digit of the
* integer in English. So, if the user types in 932, the
* program should display >>> nine three two <<<.
* (Remember to display “zero” if the user types in
* just a 0.)
*/
/*USING IF-ELSE IF*/
#include <stdio.h>
#include <stdlib.h>
int main (void)
{
int rem,num,sum=0,rem1;
printf("enter the number:\n");
scanf("%i",&num);
if(num<0)
{
printf("minus ");
num=-num;
}
if(num==0)
{
printf("zero");
}
while(num!=0)
{
rem=num%10;
num=num/10;
sum=sum*10 +rem;
}
/*printf("%i\n",sum);*/
while(sum!=0)
{
rem1=sum%10;
sum=sum/10;
if(rem1==0)
{
printf("zero ");
}
else if(rem1==1)
{
printf("one ");
}
else if(rem1==2)
{
printf("two ");
}
else if(rem1==3)
{
printf("three ");
}
else if(rem1==4)
{
printf("four ");
}
else if(rem1==5)
{
printf("five ");
}
else if(rem1==6)
{
printf("six ");
}
else if(rem1==7)
{
printf("seven ");
}
else if(rem1==8)
{
printf("eight ");
}
else if(rem1==9)
{
printf("nine ");
}
else
{
printf("invalid no");
}
}
return 0;
}
I'm making this program using switch statements that will assign letter grades based on if the user enters numbers 0 - 10. If the user enters a number that is not 0-10, the program outputs an error message and has the user re-enter. However, if the user enters a character the program will loop at the default case. I want it to output the error message from the default case once, and have them re-enter if they enter a character. I'm not sure as to why it loops the default case when a character is entered though.
#include <stdio.h>
int main()
{
int grade;
int r;
while((r = scanf("%i", &grade)) != EOF)
{
switch(grade)
{
case 10:
case 9:
printf("Your grade is an A\n");
break;
case 8:
printf("Your grade is a B\n");
break;
case 7:
printf("Your grade is a C\n");
break;
case 6:
printf("Your grade is a D\n");
break;
case 5:
case 4:
case 3:
case 2:
case 1:
case 0:
printf("Your grade is an F\n");
break;
default:
printf("Invalid score, please re-enter\n");
}
}
return 0;
}
Try something like:
#include <stdio.h>
int main()
{
int grade;
int r=0;
while(r != 1)
{
scanf("%i", &grade);
switch(grade)
{
case 10:
case 9:
printf("Your grade is an A\n");
r=1
break;
case 8:
printf("Your grade is a B\n");
r=1
break;
case 7:
printf("Your grade is a C\n");
r=1
break;
case 6:
printf("Your grade is a D\n");
r=1
break;
case 5:
case 4:
case 3:
case 2:
case 1:
case 0:
printf("Your grade is an F\n");
r=1
break;
default:
printf("Invalid score, please re-enter\n");
break;
}
}
return 0;
}
This will clear the input buffer on an invalid input and allow a retry.
#include <stdio.h>
int main()
{
int grade;
int r;
while((r = scanf("%i", &grade)) != EOF)
{
if ( r != 1) {//r == 1 is successful input of integer
grade = -1;//reset grade on invalid input
}
switch(grade)
{
case 10:
case 9:
printf("Your grade is an A\n");
break;
case 8:
printf("Your grade is a B\n");
break;
case 7:
printf("Your grade is a C\n");
break;
case 6:
printf("Your grade is a D\n");
break;
case 5:
case 4:
case 3:
case 2:
case 1:
case 0:
printf("Your grade is an F\n");
break;
default:
printf("Invalid score, please re-enter\n");
while ( getchar() != '\n');//clear input buffer
}
}
return 0;
}
The reason your code always loops is because there is no way to exit out of your while other than to kill the program. Remember that break only breaks out of the inner-most switch or loop.
The cleanest way to break out of multiple levels is to use a flag. One way to do what you want is like this:
bool valid_grade = false;
while(!valid_grade && (r = scanf("%i", &grade)) != EOF)
{
valid_grade = true;
switch(grade)
{
case 10:
// unchanged from your code
default:
valid_grade = false;
printf("Invalid score, please re-enter\n");
}
}
I am a totally newbie about C programming. so my program is very long, sorry.
my professor wants to have a number system- binary to decimal, decimal to binary, octal to decimal, hexadecimal to binary. he also want to have a loop( if he wants to exit press [E], if not then press any key). Now i'm having a problem with this hexadecimal because it keeps saying " type mismatch in redeclaration" and i don't know now how to solve this problem.
so heres my not yet finished program because of "hexadecimal" problem. help me with this error. don't mind the octal to decimal, I am currently programming it :)
#include<stdio.h>
#include<conio.h>
#include<math.h>
#define MAX 1000
long num, decimal(long), octal(long), binary(long),j;
char hexadecimal(char), k[MAX];
main()
{
char choice;
clrscr();
printf("[B]inary to Decimal\n");
printf("[D]ecimal to Binary\n");
printf("[O]ctal to Decimal\n");
printf("[H]exadecimal to Binary\n");
printf("[E]xit\n");
printf(" Enter your choice....");
choice=getche();
switch(choice)
{
case 'b':
case 'B': binary(j); break;
case 'd':
case 'D': decimal(num); break;
case 'o':
case 'O':
case 'h':
case 'H': hexadecimal(k[MAX]); break;
case 'e':
case 'E': return 0;
default: printf("\n Invalid choice.... press any key to REPEAT");
getch();
main();
}
printf("\nDo you want to [E]xit?");
choice=getch();
switch(choice)
{
case 'e':
case 'E': printf("\nInvalid choice... press any key to repeat");
getch();
main();
}
getch();
return 0;
}
long binary(long j)
{
long binary_val,decimal_val=0, base=1, rem;
printf("Enter a binary number( 1s & 0s): ");
scanf("%ld",&j);
binary_val=j;
while(j>0)
{
rem=j % 10;
decimal_val=decimal_val + rem * base;
j= j/ 10;
base=base * 2;
}
printf(" The Binary Number is %ld\n",binary_val);
printf(" Its decimal equivalent is = %d\n",decimal_val);
}
long decimal(long num)
{
long decimal_num, remainder, base=1, binary=0;
printf(" \nEnter a decimal integer: ");
scanf("%ld",&num);
decimal_num=num;
while(num>0)
{
remainder= num % 2;
binary=binary + remainder * base;
num=num/2;
base= base * 10;
}
printf(" Input number is %d\n",decimal_num);
printf(" Its binary equivalent is = %ld",binary);
}
char hexadecimal(char k[MAX])
{
long int i=0;
clrscr();
printf(" Enter any Hexadecimal number: ");
scanf("%s",&k);
printf("\n Equivalent binary value: ");
while(k[i])
{
switch(k[i])
{
case '0': printf("0000"); break;
case '1': printf("0001"); break;
case '2': printf("0010"); break;
case '3': printf("0011"); break;
case '4': printf("0100"); break;
case '5': printf("0101"); break;
case '6': printf("0110"); break;
case '7': printf("0111"); break;
case '8': printf("1000"); break;
case '9': printf("1001"); break;
case 'a':
case 'A': printf("1010"); break;
case 'b':
case 'B': printf("1011"); break;
case 'c':
case 'C': printf("1100"); break;
case 'd':
case 'D': printf("1101"); break;
case 'e':
case 'E': printf("1110"); break;
case 'f':
case 'F': printf("1111"); break;
default: printf("\n Invalid hexadecimal digit %c",k[i]); return 0;
}
i++;
}
}
The error you are getting type mismatch in redeclaration of hexadecimalis a result of the difference between the function you prototyped and implemented.
Your prototype is:
char hexadecimal(char), k[MAX];
This line prototypes a function hexadecimal that returns a char and takes a char as an argument AND this line also declares a global char array k of size MAX.
Your actual function is:
char hexadecimal(char k[MAX])
This function is a function that returns a char, but instead of taking a char like your prototype it instead takes a char array of size MAX. As you can see the prototyped function and the function itself are not the same. By making the functions exactly the same you will fix your issue.
To be honest, you don't need to pass anything into that function nor make a global char array as you can locally hold the array based on your code. The only other time you use the array you just pass it to this function which means it is better of as a local to that function anyway. So, you can simply do this:
char hexadecimal(void)
{
char k[MAX]
//same code below...
Now the function takes no arguments and k is still declared in the function, but is local instead of global. The prototype for this function would simply be:
char hexadecimal(void);
I have been able to do switch case program but I want program to run again and again until a user selects to quit.
I basically wants program to run again and again using do while loop...
switch(I)
{
case 1:
printf("67");
break;
case 2:
printf("45");
break;
default:
printf("default");
}
Use a do...while loop like this:
int I = 1; //Initialize to some non-zero number to prevent UB
printf("Enter 0 to quit \n");
do{
if (scanf("%d",&I) != 1) //If invalid data such as characters are inputted
{
scanf("%*[^\n]");
scanf("%*c"); //Clear the stdin
}
} while(I!=0); //Loop until `I` is not 0
This piece of code will loop until the user enters 0. You can change this code according to your needs. If you want your switch in this, copy your posted code after the scanf.
The loop will run until you enter -1 as input.
#include<stdio.h>
int main()
{
int I;
do
{
puts("Enter -1 to quit");
printf("Enter your choice: ");
scanf("%d",&I);
switch(I)
{
case 1:
printf("67\n");
break;
case 2:
printf("45\n");
break;
case -1:
puts("Bye");
break;
default:
printf("default\n");
}
}while(I != -1);
return 0;
}
this program runs untill user gives input 0 or a negative number...
#include<stdio.h>
int main()
{
int I;
do
{
scanf("%d",&I);
switch(I)
{
case 1:
printf("67");
break;
case 2:
printf("45");
break;
default:
printf("default");
}
}
while(I>0);
return 0;
}
Simple Use of Do-While Loop.
Choice is the variable in which user's choice will be stored, whether he wants to print the statement again or not.
int choice;
do{
printf("\nHello World!"); //This is the task of the program (Replace it with your task)
printf("\nDo You Want to Print it again ? 1 Yes/0 No: ");
scanf("%d",&choice);
}while(choice==1); //Loop will exit when choice gets value other than 1
// here switch will run until A is not equal to S
int N;
char A;
do{
cin>>N;
N = N%7;
cout<<endl;
cin>>A;
switch(N)
{
case 1: cout<<"Monday"<<endl; break;
case 2: cout<<"Tuesday"<<endl; break;
case 3: cout<<"Wednesday"<<endl; break;
case 4: cout<<"Thursday"<<endl; break;
case 5: cout<<"Friday"<<endl; break;
case 6: cout<<"Saturaday"<<endl; break;
case 0: cout<<"Sunday"<<endl; break;
default: cout<<"Invalid Input"; }}
while(A!='S');