quit on non integer?

[Matt You]

I have a simple program (code follows) that circle_shifts an array, but I need it to be able to quit when the user enters a character, (ex. q). Where do I start?

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

int printAr(int n[], const int SIZE){
  unsigned int i;
  printf("Array contents: ");
  for( i=0 ; i<SIZE ; i++ ){
    printf("%d ", n[i]);
    }
  printf("\n");
  }

int shifty(int userAns, int n[], const int SIZE){
  int i, j; //counter
  int temp_pivotNum;

  for( j=0 ; j<(sqrt(userAns*userAns)) ; j++ ){
    if( userAns >= 0 ){
      temp_pivotNum = n[SIZE-1];
      for( i=(SIZE-1) ; i>0 ; i-- ){
        n[i] = n[i-1];
        }
      n[0] = temp_pivotNum;
      }
    else{
      temp_pivotNum = n[0];
      for( i=0 ; i<(SIZE-1) ; i++ ){
        n[i] = n[i+1];
        }
      n[SIZE-1] = temp_pivotNum;
      }
    }
  }

int main(){
  const int SIZE = 10; 
  int n[SIZE], i, userNum;
  int userAns;

  for( i=0 ; i<SIZE ; i++ ){
    n[i] = i+1;
    }
  printAr(n, SIZE);

  while( 1 ){  //while(1) is temporary
    printf("Shift how many positions? ");
    scanf("%d", &userAns);
    shifty(userAns, n, SIZE);
    printAr(n, SIZE);
    }
  }

[Dave Sinkula]

http://www.daniweb.com/code/snippet441.html ?

[WaltP]

By not using scanf() to input your data. See this series to see why, and how to fix it.

[Matt You]

Thanks guys. Here's the solution btw:

int intCheck(){
  int userNum, count = 0;
  int SIZE = 5;
  char userNum_asChar[SIZE];
  int negFlag;

  fgets ( userNum_asChar, SIZE, stdin );

  printf( "String %s", userNum_asChar );
  negFlag = (userNum_asChar[0] == '-')? 1 : 0 ;
  printf("Negative flag %d\n", negFlag);

  if( userNum_asChar[negFlag] >= '0' && userNum_asChar[negFlag] <= '9' ){
    userNum = userNum_asChar[negFlag]-'0';
    userNum -= (negFlag)? userNum*2 : 0 ;
    printf("userNum %d\n", userNum);
    return userNum;
    }
  else{
    printf("Non number %c\n", userNum_asChar[1]);
    }
  }