Stack : not able to push a couple of characters in

问题:

I have a code to implement a stack using array, here the complete code : here

The case is why I cannot to push more than one character, but only one character? but I've been clicking some variables are initialized using a struct for her push some characters in the form of an array:

struct stackMhs {
char nama[10];
char npm[10];
char telp[10];
int size;
};

struct stackMhs stackMhsbaru;

This is the push() function with a parameter which will be the contents of data in the function main():

void push(char nm, char np, char tel) {
if(stackMhsbaru.size != 10) {
stackMhsbaru.nama[stackMhsbaru.size + 1] = nm;
stackMhsbaru.npm[stackMhsbaru.size + 1] = np;
stackMhsbaru.telp[stackMhsbaru.size + 1] = tel;
stackMhsbaru.size++;
}
else {
printf("stack is full!");
}
}

The problem is when I use ' to fill data is only one character at the push() function like push('a','b','c'); when at compile no errors, but when I use " such as push("aa","bb","cc"); when at compile error occurs:

main.c: In function 'main':
main.c:60:6: warning: passing argument 1 of 'push' makes integer from pointer without a cast [-Wint-conversion] 
 push("aa", "bb", "cc"); 
      ^ 
main.c:23:6: note: expected 'char' but argument is of type 'char *'
void push(char nm, char np, char tel) {
     ^
main.c:60:12: warning: passing argument 2 of 'push' makes integer from pointer without a cast [-Wint-conversion]
push("aa", "bb", "cc");
           ^
main.c:23:6: note: expected 'char' but argument is of type 'char *'
void push(char nm, char np, char tel) {
     ^
main.c:60:18: warning: passing argument 3 of 'push' makes integer from pointer without a cast [-Wint-conversion]
push("aa", "bb", "cc");
                 ^
main.c:23:6: note: expected 'char' but argument is of type 'char *'
void push(char nm, char np, char tel) {
     ^ 

My question is : any solution ?

回答1:

In C, anything inside a '' is a character (declared using char) and anything inside "" represents a string which is a null terminated array of chars.

You cannot assign an array of chars to a single char variable, hence you see the warnings.

Explanation of the warning:

warning: passing argument 1 of 'push' makes integer from pointer without a cast

For explanation sake, assume that the compiler means char when it says int, then basically it is complaining that you are trying to assign a char array type to a char without explicitly telling compiler that you want to do so.

Correct way of doing what you are trying:

Pass the string character by character to the push function called inside a loop.

回答2:

First you should try to care more about your code indentation, it would be easier for us to read it.

Now, for your problem : there is a huge difference in C between 'c' and "c". The first is just a character and the second is a null terminated array of characters, which is totally different.

When you call push("aa", "bb", "cc");, you are giving 3 arrays of characters to a function needing 3 characters, this is why your code does not works.

To bypass this, you can call your function multiple time with all the different characters of your array of characters :

char *str = "foo";
while (*str)
    push(*(str++));

This way, the while will loop in your string and call the push() function will all the characters available in str.