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# Case statement

 P: n/a I've set up a case statement to have my program determine where on the Cartesian plane a point the user enters is located. I keep getting the C2051 error when I compile. Any help? #include #include using namespace std; int main() { //declare variables int var1, var2; //get the points cout << "Enter 2 numbers that are the coordinates on a Cartesian plane: "; cin >> var1 >> var2; cout << endl << endl; //use a case statment to determine the plane switch (var1 & var2) { case (var1 == 0) && (var2 == 0): cout << "(" << var1 << "," << var2 << ")" << " is on the origin." << endl; break; case ((var1 >= 1) || (var1 <= -1)) && (var2 == 0): cout << "(" << var1 << "," << var2 << ")" << "is on the x axis." << endl; break; case (var1 == 0) && ((var2 >= 1) || (var2 <= -1)): cout << "(" << var1 << "," << var2 << ")" << "is on the y axis." << endl; break; case (var1 >= 1) && (var2 >= 1): cout << "(" << var1 << "," << var2 << ")" << " is in the first quadrant." << endl; break; case (var1 <= -1) && (var2 >= 1): cout << "(" << var1 << "," << var2 << ")" << " is in the second quadrant." << endl; break; case (var1 <= -1) && (var2 <= -1):cout << "(" << var1 << "," << var2 << ")" << " is in the third quadrant." << endl; break; case (var1 >= 1) && (var2 <= -1): cout << "(" << var1 << "," << var2 << ")" << " is in the fourth quadrant." << endl; break; } return 0; } Sep 10 '05 #1
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 P: n/a deanfamily11 wrote: I've set up a case statement to have my program determine where on the Cartesian plane a point the user enters is located. I keep getting the C2051 error when I compile. Any help? An `error number' is specific to your compiler -- and meaningless in this context. #include #include using namespace std; int main() { //declare variables int var1, var2; //get the points cout << "Enter 2 numbers that are the coordinates on a Cartesian plane: "; cin >> var1 >> var2; cout << endl << endl; //use a case statment to determine the plane switch (var1 & var2) Somehow, I suspect that you don't want the bitwise `and' of the variables that were input. { case (var1 == 0) && (var2 == 0): cout << "(" << var1 << "," << var2 << ")" Case labels must be constants. *Please* get an appropriate book (see http://www.accu.org for possibilities) -- and study. You, as of yet, have no clue as to the syntax of C++. [snip] HTH and Cheers, --ag -- Artie Gold -- Austin, Texas http://goldsays.blogspot.com (new post 8/5) http://www.cafepress.com/goldsays "If you have nothing to hide, you're not trying!" Sep 10 '05 #2

 P: n/a deanfamily11 wrote: I've set up a case statement to have my program determine where on the Cartesian plane a point the user enters is located. I keep getting the C2051 error when I compile. Any help? Error codes are compiler-specific, so in the future you should indicate the actual error message, not the code. One problem you have is that you are using runtime expressions in your case statements. Each case in a switch statement must contain a distinct compile-time constant. You cannot use expressions that are evaluated at runtime. switch (var1 & var2) This is technically okay, but I doubt you want to use the & operator. { case (var1 == 0) && (var2 == 0): cout << "(" << var1 << "," << var2 << This is not okay. You will need to use a nested if statement to do this. Gregg Sep 10 '05 #3

 P: n/a Well, then the text of the error is "case expression not constant" and it occurs on every line of the case statement. "Artie Gold" wrote in message news:3o************@individual.net... deanfamily11 wrote: I've set up a case statement to have my program determine where on the Cartesian plane a point the user enters is located. I keep getting the C2051 error when I compile. Any help? An `error number' is specific to your compiler -- and meaningless in this context. #include #include using namespace std; int main() { //declare variables int var1, var2; //get the points cout << "Enter 2 numbers that are the coordinates on a Cartesian plane: "; cin >> var1 >> var2; cout << endl << endl; //use a case statment to determine the plane switch (var1 & var2) Somehow, I suspect that you don't want the bitwise `and' of the variables that were input. { case (var1 == 0) && (var2 == 0): cout << "(" << var1 << "," << var2 << ")" Case labels must be constants. *Please* get an appropriate book (see http://www.accu.org for possibilities) -- and study. You, as of yet, have no clue as to the syntax of C++. [snip] HTH and Cheers, --ag -- Artie Gold -- Austin, Texas http://goldsays.blogspot.com (new post 8/5) http://www.cafepress.com/goldsays "If you have nothing to hide, you're not trying!" Sep 10 '05 #4

 P: n/a On Sat, 10 Sep 2005 03:51:48 GMT, "deanfamily11" wrote: I've set up a case statement to have my program determine where on theCartesian plane a point the user enters is located. I keep getting theC2051 error when I compile. Any help? //use a case statment to determine the plane switch (var1 & var2) { case (var1 == 0) && (var2 == 0): cout << "(" << var1 << "," << var2 << You can't do that... The expressions in a case statement must evaluate to a constant integer at compile time. The switch expression will compile, but will not work as you expect, because it will also be evaluated as an integer, but at run time. Sep 10 '05 #5

 P: n/a deanfamily11 wrote: Well, then the text of the error is "case expression not constant" and it occurs on every line of the case statement. Well exactly case 1: case 2: case 3: case 4: these are OK, the case expressions are constants case (var1 == 0) && (var2 == 0): this is not OK, the case expression is not a constant. You want an if statement not a case statement if ((var1 == 0) && (var2 == 0)) { ... } else if (((var1 >= 1) || (var1 <= -1)) && (var2 == 0)) { ... } etc. john Sep 10 '05 #6

 P: n/a "deanfamily11" wrote in message news:oLsUe.576\$vQ3.44@trnddc08... I've set up a case statement to have my program determine where on the Cartesian plane a point the user enters is located. I keep getting the C2051 error when I compile. Any help? #include #include using namespace std; int main() { //declare variables int var1, var2; //get the points cout << "Enter 2 numbers that are the coordinates on a Cartesian plane: "; cin >> var1 >> var2; cout << endl << endl; //use a case statment to determine the plane switch (var1 & var2) { case (var1 == 0) && (var2 == 0): cout << "(" << var1 << "," << var2 << ")" << " is on the origin." << endl; break; case ((var1 >= 1) || (var1 <= -1)) && (var2 == 0): cout << "(" << var1 << "," << var2 << ")" << "is on the x axis." << endl; break; case (var1 == 0) && ((var2 >= 1) || (var2 <= -1)): cout << "(" << var1 << "," << var2 << ")" << "is on the y axis." << endl; break; case (var1 >= 1) && (var2 >= 1): cout << "(" << var1 << "," << var2 << ")" << " is in the first quadrant." << endl; break; case (var1 <= -1) && (var2 >= 1): cout << "(" << var1 << "," << var2 << ")" << " is in the second quadrant." << endl; break; case (var1 <= -1) && (var2 <= -1):cout << "(" << var1 << "," << var2 << ")" << " is in the third quadrant." << endl; break; case (var1 >= 1) && (var2 <= -1): cout << "(" << var1 << "," << var2 << ")" << " is in the fourth quadrant." << endl; break; } return 0; } You have case statement syntax wrong, and it won't work for what you want. it's: switch ( expression ) statement case constant-expression : statement default : statement Notice the case takes a constant-expression. == is already "built in". Such as: switch( c ) { case 'A': capa++; break; case 'a': lettera++; break; default : total++; } Notice, NOT case ( c == 'a' ), but case 'A': You could do more than one... case 'A': case 'B': case 'C': std::cout << "A to C" << std:endl; break; So, it's not going to do what you want. A case statement can't check for=, only == You'll need to use some other form of construct, I'd use if statements, and, to be truthful, your whole block is in the form of a big if statement block anyway with a little format adjusting. if ( (var1 == 0) && (var2 == 0) ) cout << "(" << var1 << "," << var2 << ")" << " is on the origin." << endl; else if ( ((var1 >= 1) || (var1 <= -1)) && (var2 == 0) ) cout << "(" << var1 << "," << var2 << ")" << "is on the x axis." << endl; else if ( (var1 == 0) && ((var2 >= 1) || (var2 <= -1)) ) cout << "(" << var1 << "," << var2 << ")" << "is on the y axis." << endl etc... Sep 11 '05 #7

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