Unresolved external 'atoi'

[Would]

Hey, hopefully one of you can help me... I keep getting an unresolved external 'atoi(char)' and I dont know why.. here is the code

#include <iostream>
#include <stdlib.h>
using namespace std;


void main()
{
int atoi(char c);
int a, b, c, d, e, f, g;
int const row = 10;
int const col = 4;
char array[row];
char phonenum[row][col] = {
{ "0***"},
{ "1***"},
{ "2ABC"},
{ "3DEF"},
{ "4GHI"},
{ "5JKL"},
{ "6MNO"},
{ "7PRS"},
{ "8TUV"},
{ "9WXY"} };

cout<< "enter number" <<endl;
cin>> array;

for(a = 0; a < 3; a++)
{
for(b = 0; b < 3; b++)
{
for(c = 0; c < 3; c++)
{
for(d = 0; d < 3; d++)
{
for(e = 0; e < 3; e++)
{
for(f = 0; f < 3; f++)
{
for(g = 0; g < 3; g++)
{
cout<< phonenum[atoi(array[0])][a], phonenum[atoi(array[1])][a], phonenum[atoi(array[2])][c], phonenum[atoi(array[3])][d], phonenum[atoi(array[4])][e], phonenum[atoi(array[5])][f], phonenum[atoi(array[6])][g];
}

}
}
}
}
}
}
}

[svlsr2000]

The standard library declares atoi as

int atoi ( const char * str );.Though c++ allows function overloading You should define your function. :)

[Would]

im not sure what you mean by define my function I have it initialized and the header file what else should i do here?

[mac11]

int atoi(char c);

You don't need this line if you want to use the atoi() thats provided by stdlib.h. If you want to write your own atoi function (overload it) you should move this line outside of main and add a function body to it....

Most likely, you want to use the stdlib atoi() so just remove that line and adjust your code to work with it.

[Would]

when i remove the initialization for the atoi in my code it says "could not find a match for atoi(char) in function main.. im completely lost here we didnt cover this in class my teacher just suggested it for the route i am going with this code

[Would]

i invite anyone to tell me whats going on here please!

[svlsr2000]

stdlib.h defines/ declares atoi as int atoi(char *); You are trying to use atoi(char)

[svlsr2000]

#include <iostream>
#include <stdlib.h> 
using namespace std;
 
 
void main()
{
int atoi(char c);
int a, b, c, d, e, f, g;
int const row = 10;
int const col = 4;
char array[row];
char phonenum[row][col] = { 
{ "0***"},
{ "1***"},
{ "2ABC"},
{ "3DEF"},
{ "4GHI"},
{ "5JKL"},
{ "6MNO"}, 
{ "7PRS"},
{ "8TUV"},
{ "9WXY"} };
 
cout<< "enter number" <<endl;
cin>> array;
 
for(a = 0; a < 3; a++)
{
for(b = 0; b < 3; b++)
{
for(c = 0; c < 3; c++)
{
for(d = 0; d < 3; d++)
{
for(e = 0; e < 3; e++)
{
for(f = 0; f < 3; f++)
{
for(g = 0; g < 3; g++)
{
cout<< phonenum[atoi(array[0])][a], phonenum[atoi(array[1])][a], phonenum[atoi(array[2])][c], phonenum[atoi(array[3])][d], phonenum[atoi(array[4])][e], phonenum[atoi(array[5])][f], phonenum[atoi(array[6])][g];
}
 
}
}
}
}
}
} 
}
 

in phonenum[atoi(array[0])][a], array [0] is treated as character and not as pointer to character. atoi expects pointer to string, ie you can say array of character terminated with null.

[Would]

i honestly dont know enough about c++ to know what you mean by that...

[svlsr2000]

char a[] = "hello";

here a can be used as a pointer. The compiler terminates this with Null for us.
Here 'a' can also be used as pointer to string.

a[0], a[1] and so on are treated as character.

In your call to atoi, your using array[0], which is treated as character, where as atoi expects pointer to string or character.

I thing this answers your question