programming

/* else, it will be an integer.*/ else { int temp = atoi(argv[i]); push (temp); //int i = 0; printf("Stack: %d", stack[top]); //printf("Integer: %d\n",atoi(argv[i])); }

/* * **** HISTORY ***** * * Filename: test.c * Synopsis: test * * This is a simple program that will take input from the keyboard and then * print each line of input to screen. * Version 0.1 - Program simply returned a string of characters that had been * entered using printf. * version 0.2 - program differentiated between a string of characters and an * integer. * version 0.3 - Fixed a bug in the code that caused a 0 integer to be printed * after characters. Originally believed it to be a null byte, later discovered * that it was, in fact, a flaw in my if statements since I hadn't used else. * the use of else and else if in the testing area of the program are important * so that characters aren't printed as characters then passed down to be converted * into integers. * version 0.4 - program began to differentiate between characters, an operand * and the specific operators +, -, /, x and =. I was able to tell that the * differentiation had been made by asking the program to print out which each * was, for example: If I had entered: test 1 a + the program would output: * Integer: 1, Character: a, Symbol +. * version 0.5 - Array was defined from code that had been written in p3.c which was * written at an earlier date. This is where p3.c and test.c began to merge as * the final solution to p3.c with p3.c merging into test.c. */ #include #include /* * define is used to make modification of each easier. It is also good for readability. * Characters A - D will be assigned values that the user wishes to store so that they * can later be used by, for example, 2 A +. */ #define stack empty #define MemoryA A #define MemoryB B #define MemoryC C #define MemoryD D /* * I need to define my array that will be used in a similar way to how I understand a * stack. The type of array that I will use is a fixed-length array so that the program * size will have a limit of 20 elements. * See Page 112 - C In a Nutshell */ int top = 0; /*Pointer to keep track of where the top of the stack/array is*/ //int maxstack = 20; /*Allocates the maximum value of the stack-array */ int stack[50]; /*sets the array stack equal of the maximum value of the stack*/ void push(int x); /* * The push function will push a new entry onto the stack at the stack pointer "top". * Once the entry (passed in as x) has been assigned as an element to the stack the * "stack pointer" top will then increment by one so that it is pointing to the next * free space. */ void push(int x) { stack[top] = x; top ++; } int main (int argc, char *argv[]) { int i; int j = 0; for (i = 1; i < argc; i++) { for(j=0; j < strlen(argv[i]); j++) { /*This is a test to see if a the input is a * alphabetical number. If it is, then the * program will then check to see if it is * specifically A, B, C or D. */ if (isalpha(argv[i][j])) { printf("Character: %s\n", argv[i]); } /* These tests will test to see if input is an operand*/ else if (strcmp(argv[i], "+") == 0) { printf("Symbols: %s\n", argv[i]); } else if (strcmp(argv[i], "-") == 0) { printf("Symbols: %s\n", argv[i]); } else if (strcmp(argv[i], "/") == 0) { printf("Symbols: %s\n", argv[i]); } else if (strcmp(argv[i], "x") == 0){ printf("Symbols: %s\n", argv[i]); } /* else, it will be an integer.*/ else { int temp = atoi(argv[i]); push (temp); //int i = 0; printf("Stack: %d", stack[top]); //printf("Integer: %d\n",atoi(argv[i])); } } } }

I'm finding C difficult to understand. I'm working using two books: C in a Nutshell and I'm referencing with Comprehensive C (which is old but it was free.) The problem I'm trying to solve is to create a Reverse Polish Notation calculator. I'm using an array as a stack and the basic principle is:
for input (from command prompt) 2 1 +
Push 2 on the stack. Push 1 onto the stack. Meet operator, pop two and then push answer onto the stack.

But I'm having problems with my main method, particularly with the C syntax. This is my main method so far:

/*
* I need a way for the program to read input separated by space, where a space will
* indicate the end of a value. For example: 23 3 is the input twenty three and three,
* not: two, three, three.
*
* When an integer operand is encountered, it will be pushed onto the stack. An operator
* will cause two items of the stack of be popped then a push of the answer.
    argc = SIZE OF THE ARRAY
    argv = Array of strings that represents the command line entered.
*/

int main (int argc, char *argv)

{
    int i;
    for (i = 1; i < argc; i++)
    {
        if (x argv = int)
        {
            push(int x)

                //http://www.cppreference.com/stdstring/isdigit.html
                //http://www.cppreference.com/stdstring/atoi.html
    }
}

The hyperlinks are a link to two methods from the library that I need to use: isdigit() and atoi(). Because the input is being entered from the command prompt it's my understanding that a character and an integer cannot be differentiated simply by their bit pattern. What I need to do with the input is take the "string", convert it to an integer and then check to see if it is an integer or not.

Now, in Java I'd do something like x.isdigit().atoi() but... gah! There's a lot of true/false requirements in there and I don't think I actually fully understand exactly what I'm trying to do.

Scanner scanDie = new Scanner(System.in); // first scanner System.out.println("Enter number of dice"); int n = scanDie.readInt(); // this is where user enters # of dice if (n < 0) // if user enters # less than 0 System.out.println("Error: Number must be 0 or greater."); // there will be an error Scanner scanScore = new Scanner(System.in); // second scanner SimpleDice d = new SimpleDice(); System.out.println("Enter score"); int m = scanScore.readInt(); // this is where user enters score if (m < 0) // if user enters score less than 0 System.out.println("Error: Score must be 0 or greater"); // there will be an error int tossCount = 100000; // this is the total # of tosses (designated by assignemnt) int scoreCt = m; // this is saying that the # the user entered (m) is now the score count int tossResult; for(int j = 0; j < tossCount; j++){ // for loop used to add up tosses tossResult = d.throwDice(); if(tossResult == m) scoreCt++;} System.out.println("Success Rate: " + ((double)scoreCt)/tossCount); // this divides the #of times m occurred by the #of times the dice were rolled