Need help with my C program.

[Cammaaron]

When I try to run my program I will get a Segmentation fault error.

When I compile the code I get the warnings

math.c: In function ‘programone’:
math.c:63: warning: format ‘%f’ expects type ‘float *’, but argument 2 has type ‘double’
math.c:65: warning: format ‘%f’ expects type ‘float *’, but argument 2 has type ‘double’
math.c:67: warning: format ‘%f’ expects type ‘float *’, but argument 2 has type ‘double’


Here is the source code, I got line 63, 65, and 67 marked with ">>> "

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int jsw_flush(void);
int programone(void);
int main()
{
char c;
for (;;)
{
printf("1: solve for right triangle \n");
printf("0: Exit program\n");
printf("\nSelect Your choice: ");
c = getchar();
jsw_flush();
printf("\n");
if(c=='0')
{
break;
}
switch (c)
{
case '1':
programone();
break;
case '0':
break;
default:
printf("wrong choice\n");
break;

}
}
return(0);
}

int jsw_flush (void)
{
int ch; /* getchar returns an int */

/* Read characters until there are none left */
do
ch = getchar();
while (ch != EOF && ch != '\n');

clearerr (stdin); /* Clear EOF state */
}

programone(void)
{

float x = 0.0;
float y = 0.0;
float z = 0.0;
float answer = 0.0;
char c;
for (;;)
{
printf("Please enter what numbers you know for the triangle\n");
printf("If all numbers are entered, it will test to see if this is a right triangle\n");
printf("\nWhat is the first side: ");
>>> scanf("%f",x);
printf("\nWhat is the second side: ");
>>> scanf("%f",y);
printf("\nWhat is the long side: ");
>>> scanf("%f",z);
printf("\n");
if (x = 0)
{
x = (sqrt(pow(z,2)-pow(y,2)));
printf ("The answer is : %f.\n", x);
}
else if (y = 0)
{
y = (sqrt(pow(z,2)-pow(x,2)));
printf ("The answer is : %f.\n", y);
}
else if (z=0)
{
z=(sqrt(pow(x,2)+pow(y,2)));
printf("The answer is : %f\n",z);
}
else if (x!=0&&y!=0&&z!=0)
{
answer = (sqrt(pow(x,2) + pow(y,2)));
if (answer=z)
{
printf ("This is a right triangle.\n");
}
else
{
printf ("This is not a right triangle.\n");
}
}

printf("Do you want to another one? (y or n)\n");
c = getchar();
jsw_flush();
if (c!='y'||c!='Y')
{
break;
}


}
}

[Queue29]

You need an ampersand in front of the x, y, and z.

http://www.cplusplus.com/reference/clibrary/cstdio/scanf/

ex:

scanf("%f", &x);

[dwhitney67]

Here's your code again, but with the syntax errors corrected.



#include <stdio.h>
#include <stdlib.h>
#include <math.h>

void jsw_flush(void); void programone(void); int main(void) { char c; for (;;) { printf("1: solve for right triangle \n"); printf("0: Exit program\n"); printf("\nSelect Your choice: "); c = getchar(); jsw_flush(); printf("\n"); if(c=='0') { break; } switch (c) { case '1': programone(); break; case '0': break; default: printf("wrong choice\n"); break; } } return(0); } void jsw_flush (void) { int ch; /* getchar returns an int */ /* Read characters until there are none left */ do ch = getchar(); while (ch != EOF && ch != '\n'); } void programone(void) { float x = 0.0; float y = 0.0; float z = 0.0; float answer = 0.0; char c; for (;;) { printf("Please enter what numbers you know for the triangle\n"); printf("If all numbers are entered, it will test to see if this is a right triangle\n"); printf("\nWhat is the first side: "); scanf("%f",&x); printf("\nWhat is the second side: "); scanf("%f",&y); printf("\nWhat is the long side: "); scanf("%f",&z); printf("\n"); if (x == 0) { x = (sqrt(pow(z,2)-pow(y,2))); printf ("The answer is : %f.\n", x); } else if (y == 0) { y = (sqrt(pow(z,2)-pow(x,2))); printf ("The answer is : %f.\n", y); } else if (z==0) { z=(sqrt(pow(x,2)+pow(y,2))); printf("The answer is : %f\n",z); } else if (x!=0&&y!=0&&z!=0) { answer = (sqrt(pow(x,2) + pow(y,2))); if (answer==z) { printf ("This is a right triangle.\n"); } else { printf ("This is not a right triangle.\n"); } } printf("Do you want to another one? (y or n)\n"); c = getchar(); jsw_flush(); if (c!='y'||c!='Y') { break; } } }



P.S. I found your code hard to read because of the crazy indenting; hopefully you will find my version equally challenging.

[trent.josephsen]

Don't use scanf for interactive input. Use fgets and pick out the number with strtod, or write your own function using getchar() and friends.

Good explanations here (http://c-faq.com/~scs/cclass/krnotes/sx10d.html) and here (http://c-faq.com/stdio/scanfprobs.html).

[smdawson]

I had a quick question about scanf. I have a do-while loop that asks the user if they want to repeat at the end of a calculation by choosing (y/n). When I run the program it doesn't stop to allow the input of a character. The problem line:


scanf("%c", &repeat);

However, when I changed it to an integer the program stopped and waited for input from the user. The line of code was changed to this:


scanf("%i", &repeat);

What am I missing?

[Bachstelze]

You probably have a newline character waiting in the input buffer. Do not forget to flush it after each input. And also do not use scanf, see the links posted by trent.